Do-it-yourself matching block for a towbar: device diagram

Author: Evgeny Zhivoglyadov. Date of publication: August 16, 2016. Category: Automotive equipment.

Modern cars are equipped with a large number of electronic accessories that allow the car owner to feel more comfortable and confident on the road. All these devices operate from the network, and accordingly consume energy. In order to ensure the correct operation of all components in cars, modern “intelligent” on-board systems began to be installed that regulate the current supply and block any devices that provoke too sudden jumps. One such device is a towbar.

After connecting the electrics of the trailer hitch, many are faced with the fact that the car’s used vehicle generates an error or completely blocks the “suspicious” node. To get rid of this problem, it is enough to install a coordination unit (Smart Connect), which will act as an “intermediary” between the on-board system and the new device. However, not all machines require such an additional module.

What is Smart Connect

Modern cars are equipped with various electronic systems for comfort and convenience. Coordinating all these systems would require a large number of cables. To solve this problem, car manufacturers use CAN-BUS or CAN bus. The signals travel only on two wires and are distributed via bus interfaces. Therefore, they are distributed to different consumers, including side lights, brake lights, turn signals, etc.

Blocking consent

If you connect the electrical equipment of the towbar with such a system, the resistance in the electrical network will immediately change. The OBD-II on-board diagnostic system will indicate the error and the corresponding circuit. Other light sources may also not function properly.

To prevent this from happening, Smart Connect is installed. To connect, a separate cable is used to the vehicle's 12V voltage. The device coordinates electrical signals without causing load changes in the vehicle's electrical network. In other words, the on-board computer does not see the additional connection. The block itself is a small box with a board, relays and contacts. This is a simple device that you can even make yourself if you wish.

In conclusion

When choosing a tow bar for a Volkswagen Polo sedan or another European car brand, give preference to quality manufacturers and their products. Now, if you have a trailer in the garage, it no longer has to gather dust. All that remains is to carry out state registration and you can use it. Good luck on the roads!

Advantages of the matching block

Coordination block for Unikit 2 ball joint before installation

If you are the owner of a modern model car, then you need to connect smart control. Without connecting the towbar hitch assembly, you simply cannot use the trailer. Here are the main benefits of installing this device:

the block completely eliminates the possibility of incorrect operation of trailer lights and prevents malfunctions in the operation of the vehicle’s electronic systems;
The unit does not respond to power surges. It is also necessary to avoid excessive loads on power circuits;
multifunctional block. Its connection makes it possible to turn on the fog lights, as well as constant control of the turn signals.

As practice shows, installing the module does not require experience, you only need attentiveness and accuracy.

Operating principles of modules

The smart connector receives a control signal from the “central nervous system” and connects a dosed load to the desired wire. The protection system built into the matching unit protects the electrical circuits and electronic “brains” of the car from overloads. The on-board computer “does not notice” the additional connection. And now we are moving on. Smart connector options come in standard or extended configurations. Basic capabilities of matching blocks:

control of direction indicators on a trailer;
fog lamp control;
recharging the trailer battery;
disabling parking sensors while connecting to a trailer.

Advanced options:

“TPP” – checking the connection of the electrical circuits of the trailer;
side light control on the left;
adjustment of the fog lamp on the left;
anti-theft option ALARM-info.

Do you have a modern car? Then the manufacturer simply left you no choice. You will not be able to use the trailer without the approval unit.

To prevent incorrect operation of the towbar lamps and prevent malfunctions in the car's electrical system, you need Smart Connect - a coordination unit that prevents an increase in the load on the on-board network. Thanks to the 15 A fuse, Smart Connect does not react to power surges.

The matching module is multitasking. It is responsible for switching the fog lamp on the trailer, controls the direction indicators on the trailer, and turns off the parking sensors when connected to the trailer.

There are coordination blocks with a large number of functions (PARK SENSOR, ALARM INFO, etc.).

A couple more nuances

Universal matching block with a set of standard connectors and fasteners

Advantages: the universal unit is cheaper than the original analogue, is compatible with the electrical system of most cars, and is not difficult to install.

Universal electrics set UniKit

The Unikit module ensures the correct operation of lighting devices and is indispensable for cars with single-filament lamps, in which different signals pass through one cable, and not through different ones.

Original block for Thule tow bar. The device is supplied with instructions and a mounting kit.

Advantages: “smart” device with an expanded range of capabilities.

The original matching block comes complete with the original tow bar. When connected, the unit automatically registers itself in the system, tests the trailer, checks the functionality of the lamps, and turns off the parking electronics and rear view cameras.

The operating diagram of the smart connect coordination block for a tow bar is quite simple. It receives data coming from the main computer systems of the vehicle, after which it redirects a strictly dosed load to the appropriate energy consumer. The peculiarity of the smart connect matching block for a towbar is that its operating scheme provides for the presence of protection systems that serve as reliable protection for all electrical circuits and computing devices of the car, protecting them from overvoltage. As a result, the host computer does not detect additional devices and continues to function as normal.

Read more: Replacing the timing belt VAZ 2110 1.5 16 valves with photos and videos

Towbar module-coordination unit UniKit

According to the set of options, there are currently two types of modules for towbars: with basic and with extended configuration. Basic set options include:

control of turn signals on a car trailer;
control of rear fog lights;
turning off the parking sensors while the vehicle is connected to a trailer;
Extended dialing options include;
control over the connection of all electrical systems of the trailer;
control of the side lighting device located on the left;
adjustment of the fog lamp, also located on the left;
protection against theft.

Equipment

When choosing a smart plug device, pay attention to the package contents:

Base. Equipping this configuration makes it possible to control the trailer's turn signals, control the fog lights, recharge the trailer's battery, and turn off the parking sensors.
Advanced. The device in this configuration has the ability to check the electrical circuit of the trailer of the connected vehicle, and also allows you to control the left side light and adjust the operation of the left fog lamp. Purchasing a more functional BSF also allows you to upgrade your car's anti-theft system.

Connection

To connect an additional module, follow the following algorithm:

The jumper is connected to the battery.
The starter, oil sensor, fuel valve and on-board computer are connected to the BSF.

Connect the ball joint hitch assembly as follows:

The cargo panels are removed and a set of cables is prepared.
Next, the running lights and brake lights are checked.
The next step is to install the smart connector.
Using the connector, connect all necessary cables to the connectors.

When to use BSF

Having bought yourself a trailer and previously installed a tow bar (or already had it from the factory), you need to connect them together. Simply using a hitch is not enough. The trailer needs to be controlled somehow: turn on the lights, brake lights, etc.

It will not be possible to connect the wiring directly, because your on-board computer will not accept such a connection. This will result in constant errors on the screen.

Now do you understand why this block is needed? Without it, the car and trailer will not be able to interact. Therefore, in the car where the on-board computer is located, you will need to purchase a Smart Connect coordination unit or a car towbar, whichever is more convenient for you.

There are several situations where a Smart Connect device is required to power your caravan:

There is a possibility of a short circuit. Due to the installation of additional electrical equipment, including trailer markers and turn signals, the load on the electrical circuit increases. The result can be blown fuses and a highly undesirable short circuit;
The vehicle is often operated without a towed vehicle (trailer). This may damage the wiring and blow the fuse;
If there is an electrical problem in the car's history, the fuse will immediately blow. This may cause damage to the lights, lights, brakes and hazard lights;
Connecting a trailer with a different pinout to the vehicle will blow the fuses and turn off the lights completely.

It doesn't matter what kind of car you have. This could be Renault Duster, Chevrolet Cruze, Ford Kuga 2013 or Kia Sportage 3rd generation. All these cars, as well as Renault Captur, Nissan Terrano, Volkswagen Tiguan, Prado 2011 150 body and even the domestic Vesta are equipped with on-board computers.

Therefore, without a matching block, the circuit will work with errors and cause various problems.

Coordination module for connecting a trailer - Community "Kulibin Club" on DRIVE2

Introduction to the essence of the problem

I won’t tell anyone a secret if I say that many car enthusiasts use various kinds of trailers, trailers, campers, etc. And if there are no problems when connecting an electrical outlet to an ordinary Zhiguli car - throw it parallel to the taillight lamps, then for modern cars this method is not suitable - the wiring is designed only for a certain current strength and exceeding the power of the lamps can lead to a fire in the wiring (I saw a burnt one wiring many times). In addition, machines of recent years of production measure the load power consumption themselves and generate an error when the standard value is exceeded. For proper connection, special matching modules are used, which cost money. (for example: for the Volks Transporter VW T5, such a factory module costs $500). Meanwhile, there is nothing complicated in this module and you can make it yourself with minimal soldering skills. By the way, it is also advisable to use the module for ordinary Zhiguli cars so as not to “overload” the wiring.

Formulation of the problem

At the moment, three approaches to creating a matching module are “fashionable”: 1) Using optocouplers and field-effect transistors myzafira.ru/forum/viewtop....php?f=71&t=1159&start=20 The most beautiful solution, but not entirely suitable for beginners, is the field device you need to be able to solder correctly so as not to burn

2) Based on electronic keys BTS443P sxem.org/2-vse-stati/razn…ya-pritsepa-k-avtomobilyu Not exactly a budget solution, but undoubtedly has the right to life

3) Using a relay A simple and effective approach, which will be discussed below

There is also a “cheat” solution - to change the lamps in the trailer lights to LEDs, but it has the disadvantage that this is possible on your own personal trailer, but what if there are several of them? or do you borrow from friends? or even for rent? then this becomes a problem.

Pay

Well, there’s not much to tell here: I didn’t draw the diagram separately due to its simplicity, all the wiring is visible in the photo below

The Sprint Layout file is available here - www.leman.cc.ua/farcop.lay6 Necessary explanations on the conclusions: Grownd and + I think there is no need to explain Reversing light - reverse lights, have 2 outputs - to the socket itself (used only on campers, therefore you don’t have to) and on the rear view camera Parking light - parking lights, they are also dimensions. Let me remind you that we are dealing with a German car whose left and right side dimensions are separate. The idea is really not bad - when parked on the side of the road, you don’t “burn out” all the lights, but only those that limit your view from the roadway. BUT in our realities, alas, it is necessary to limit it from the side of the roadside - what if someone decides to “slip through”, so we combine the left and right side signals through diodes into one relay and connect them in parallel on the socket - all of them on the trailer will light up dimensions, regardless of what lights on the tractor. Then everything is simple: Stop - stop Left Turn - left turn Right Turn - right turn I used ordinary radio relays 12 Volt 10 Ampere. Their coil resistance is 130 Ohms - this is quite enough so as not to affect the operation of lighting devices in the car. Their sizes are given below.

Diodes - any that can withstand voltage up to 20V and current up to 0.1A

It is worth noting that many, when making such boards, use connectors to connect wires of various types - whether this is correct or not can be debated, but the friend for whom I sculpted this asked to minimize the contact points, so the wires are soldered directly to the board

Unfortunately, the photo of the finished product has not been preserved, there is only a photo of the first version of the etched board (to be honest, it was unsuccessful - the tracks are too thin and although they conduct enough current, they are mechanically weak. This has already been corrected on the board above).

Full size

Connection to car

Since the car is German, we bought a “native” 13-pin connector for it at a disassembly site

Full size

I didn’t take a photo, but is it necessary to say that on the T5, a mount for it was already made from the factory, a channel was welded under the bottom to the left arch, where a rubber plug was located in the right place? I respect the Germans. The pinout of the towbar is shown, but the color of the wires may not match, so we look at the picture and “call” the tester looking for the required wire.

In the left arch we find the car wiring we need. So that

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Coordination unit for towbar electrics (Smart Connect)

The corresponding unit is an electronic device with a “smart” connection of the towbar to the vehicle. It is necessary to protect the vehicle's on-board network from overloads, since even a slight external influence can cause a disruption in the operation of the electrical circuit.

Ideal for vehicles with a sophisticated on-board computer, multiplex wiring, CAN BUS data, Check Control, electronic variable voltage control, low voltage lighting supply.

Smart Connect connects directly to the battery, making it resistant to short circuits and surges. The correct universal electrical towbar assembly has a number of important advantages:

protection of the vehicle's electrical equipment in the event of a short circuit or other malfunction of the trailer;
can be installed on cars with LED lamps;
burnt out light bulb warning

How is a tow bar useful as a device?

A towbar is also called a towing device. It is used to connect a car to a trailer for towing. Some people buy it ready-made, while others prefer to make it themselves.

Before moving on to the electrical part of attaching the tow bar, we will need to install it on the bumper. Usually it is attached to one of the towing eyes or a hole provided, which is intended for coupling, but is closed with a plug.

If you want to secure such a device with your own hands, you may need additional holes in the bottom of the machine and its side member. A welding machine and the services of an electric and gas welder may be required. Additionally, stock up on sandpaper and a grinder on which you can attach a grinding wheel.

Purchased products must correspond to a specific car model

In what cases is it necessary to install a smart connection?

In almost all modern cars, when installing a fork on a towing device, it must be connected to the on-board network through the towbar assembly. To check whether your car needs a Smart Connect module, simply unscrew one of the headlight bulbs. If the on-board computer displays information about this on the dashboard, then a corresponding unit is needed. Connecting the TSU plug directly to the rear lights in this case may lead to blown fuses and damage to the wiring.

Connecting the towbar through the appropriate unit is mandatory on vehicles equipped with:

wiring using a multiplex CAN bus, through which a digital control signal is transmitted to all devices of the machine;
automatic diagnostic system Check Control;
voltage control system;
LED lightening;
system for detecting faults and burnt out lamps;
low voltage lighting system.

Interface block (universal) ARAGON-501 MINI 7 contacts

As a rule, for all foreign cars produced after 2005, the trailer must be connected to the vehicle’s on-board network via a smart connect, except for the Volvo XC70 model produced before 2007.

But it is also advisable to install a suitable towbar on older vehicles if at least one of the following occurs:

the condition of the electrical wiring does not exclude the possibility of a fire if there is an overload in the network associated with connecting the trailer's electrical system;
before the installation of the trailer hitch, there were already failures in the on-board electrical network;
it is assumed that a rental trailer will be used, which may have a different pinout in the connection plug, which can lead to malfunctions of the entire lighting system;
The towbar will work most of the time without a trailer and there is a risk of damaging its wiring.

How to achieve a strong connection

To make the connection to the towbar even more reliable, it comes with reinforcing plates.
For the device itself, we will need holes in the body with a diameter of 12.5 to 13 mm. The tow bar itself is attached through a reinforcing plate and a nut and bolt. It is advisable to place a washer under the metal. When installing electrical wiring, try to achieve high-quality insulation to prevent moisture from entering with its destructive effect. The video in this article will help you complete all the steps of connecting the tow bar. Any work can be carried out efficiently if you carefully study the instructions before you start using the tool. On some vehicles, the rear bumper will have to be removed during installation.

It is not enough to confine yourself to screwing the hitch to the bumper of the car. An electrical outlet must also be connected to the device to be able to power the electrical consumers of the trailer itself.
There is no need to run wiring through the entire machine. Near the location of the rear lights of the car there is usually a harness to which power is supplied.
It is easy to carry out such work on your own or turn to third-party specialists with experience and skills.

Another option for a quick-release model

If you cannot immediately connect the trailer to the network of the main vehicle, you may need to purchase a so-called adapter, or matching unit.

Why are matching blocks installed in old cars?

Installing the appropriate block is relevant in the following situations:

If you accept the possibility of fire. The fact is that when connecting additional electrical appliances there is a risk of power surges.
If you plan to operate the towbar without a trailer, this can also damage the wiring and blow fuses.
If at the time of installation of the hitch and trailer there were already problems in the vehicle’s electrical circuits. In this case, the fuse will instantly burn out, and this is fraught with burnout of the brake, side and emergency lights.
If you plan to tow a trailer that is not "original" or rented. In this case, you may have a different pinout. If connected incorrectly, you risk losing all the fuses and light bulbs in the car.

If you are sure that you still need a smart connector, then you can buy it at any car market (a universal model for a tow bar will cost about 3,300 rubles) or make it yourself. If everything is clear with the purchase (preference should be given to BS from Bosal and Thule), then it’s worth talking about the homemade module in more detail.

What types of coupling devices are there?

There are the following types of towbars, based on mounting and purpose:

For example, fixed ones, which are placed on the body using bolts or welding. They are much more difficult to remove, which is why they usually last the longest. Some car owners need to be able to remove and reinstall the hitch. In this case, removable towbars will come to the rescue.
Sometimes there are flange-type devices, which are usually mounted on a special platform of the vehicle. There is a classification of towbars by tonnage, as well as the types of vehicles on which they are used.

Mountable quick release devices

Until the recent past, the hitch problem was solved much more simply - a hook was simply welded to the bracket, and there was no longer any possibility of removing such a device. Today, this approach looks, at a minimum, unreasonable, because it is better to purchase and install a towbar that can fold and hide.

Since then, the production of towbars has come a long way. In addition, the hook sticking out from the back of the car creates an additional threat to safe movement.

Coordination block for tow bar, diagram and connection algorithm

The connection diagram of the smart connector is quite simple: it receives power directly from the battery, and the control current from the corresponding rear optics cable, which receives an already decrypted analog signal, is transmitted to the socket on the towbar through a diode and a relay connected in series in the circuit. Therefore, the smart plug module simply duplicates these signals, redirecting the measured load to the trailer lights. At the same time, the circuit of the corresponding unit has reliable overvoltage protection, and the automation notices only the Smart Connect module, which consumes minimal current without causing overloads and without giving a reason to turn off the rear optics.

Smart connection diagram

The procedure for connecting the matching block is as follows:

remove both rear lights;
have with you a harness designed to connect the unit to the vehicle’s on-board network (on one side it has a connector for connecting to a smart connection, and on the other there are free ends of conductors of different colors, each of which has a special purpose);
using a tester or multimeter, find the left turn signal wire and connect it using a connector to the yellow wire of the harness;
find the left brake light wire from the rear light and connect it to the red wire; if the brake light is combined with the side lights on the car, then the red wire must be connected to the wire going to the brake light reserve;
determine the wiring through which the left side light signal is received and connect the brown wire from the unit harness;
Having found the conductor responsible for turning on the PTF, cut it off and use a connector to connect the white wire on the car side and the gray wire on the light side;
find the connection point of the ground wire of the parking sensor control unit and, disconnecting it from the car body, connect it to the purple wire;
using the end of the ring, connect the black wire of the harness to the machine body;

Using a tester or multimeter, locate the left turn signal wire

through a 15A fuse, connect the red Smart Connect power cable to the battery;
find the wire through which the right turn signal is received and use the connector to connect the green wire harness to it;
connect the blue wire of the corresponding unit to the correct size cable, the intelligent connection signal harness is connected;
connect the free ends of the cables of the second harness of the accessory kit to the towbar socket, in accordance with the pinout and purpose of each of the cables, having previously routed the harness from the installation site of the smart plug to the installation of the outlet on site (if necessary, a gasket must be installed on the harness to protect the insulation from damage) ;
Connect the wiring harnesses to the appropriate unit to the appropriate connectors and connect the unit to the vehicle body.

After installing Smart Connect, you need to connect the trailer plug and check the operation of the warning lights. Turn signals, parking lights and brake lights must be turned on, both in the car and on the trailer. When the plug is connected, the left fog light should only light up in the trailer. In a car, it will light up if you disconnect the connector on the tow bar.

After installing Smart Connect, you need to connect the trailer plug and check the operation of the warning lights

Universal electrical kit - UniKit

Tuning and repair of passenger trailers.
do-it-yourself passenger trailer types of self-assembled car trailers Modules of the Unikit (Baltex) series are designed to connect and combine the towbar electrical kit with the vehicle electronics.

Advantages:

Unlike a conventional electrical kit, when connecting the UniKit module, only the signal is removed from the rear light wires, and the module itself and the trailer are powered from the car battery using a power cable. In the event of a short circuit or immersion of the lighting equipment of towed equipment in water, only the module fuse, located in an easily accessible place, must be replaced. In this case, the wiring and fuses of the car are not affected.
Many modern cars, such as Opel Zafira, Volkswagen Tiguan, Seat Toledo, Seat Altea XL, etc., use single-filament lamps, in which, unlike two-pin lamps, different signals, for example, the parking signal and the stop signal, go along the one wire. The UniKit module, based on the supplied voltage, distinguishes the signal that needs to be supplied to the trailer, which ensures the correct operation of the trailer's lighting equipment.
The UniKit module is simply indispensable when connecting the towbar electrical kit in cars equipped with LED lights (Volkswagen B6, Volkswagen Jetta, etc.), since connecting a conventional electrical kit is impossible, because The currents going to the tail lights are very weak.
This is an inexpensive and reliable way to replace the original electrical kit.

What does installing the block give?

By installing BSF, you will receive:

coordinated operation of the electronic control unit of the vehicle and trailer;
ability to control trailer turn signals;
control of the tractor's fog lights;
the ability to disable parking sensors when connecting a trailer;
resistance of the machine's electricity to power surges;
Full short circuit protection.

All that remains is to make sure that you really need a suitable unit to connect the towbar to the car. To do this, just check a few points.

You will need Smart Connect if:

He conducted an external inspection of the car and found LEDs in the rear lights. In 90% of cases this means that you will have to buy a Black Sea Fleet;
Have you read the instructions for the car? For example, there may be concepts such as SFL or Cunbus. This also indicates the need for a block;
I paid attention to the dashboard and the screen of my BC. If there is data on external lighting devices and the current level of various fluids of the machine in operation, then SBF is needed;
He called his authorized dealer and asked about this problem. A competent solution that allows you to get an accurate and competent answer. Of course, if the consultant has the required level of awareness.

Vehicle installation

Basic procedure

First, remove the bumper and cut off the lugs. Drill holes if necessary and weld the fasteners.

Here's how to connect a trailer towbar to a car:

We will need an inspection hole on the overpass or in the garage into which we drive our vehicle.
Now we turn off the power from the mains by disconnecting the negative terminal from the battery.
Installing towbars will require removing everything from the trunk and removing its upholstery.
The device itself must be attached to the place where it is planned to be attached and the necessary markings must be made.
At the attachment point, holes are drilled on both sides with a drill, which are best treated with an anti-corrosion agent to extend service life;
As the photo for this article suggests, we can tighten the hitch using nuts, washers and bolts, as well as a suitable size wrench.
Now you need to remove the load from the car frame and provide a more reliable fastening. To do this, we make a couple of holes at the bottom of the side member and from the inside of the luggage compartment with the installation of reinforcing linings.
Tighten all the necessary bolts with wrenches.

Fastening to the car frame

Using the connection diagram

A ready-made towbar, as a rule, already has all the necessary holes for fastening, which is taken care of by the towbar manufacturers. Now we can start connecting the hitch.

We cannot do without an outlet that connects the electrical wiring of the car and the trailer. The towbar socket diagram is usually included in the kit. As for the electrical equipment of the coupling device, it consists of a plug socket with a set of wires. The color of the wiring may not match the color of the wires in the photo.

Bolted to the bracket, the socket is connected to the main wiring. When connecting, you need to look at the colors of the wires according to the diagram. You need to connect it to a standard connector, which can be 7-wire or 13-wire (only on foreign cars).

Car installation

Below are instructions with which we can connect the towbar to the electronics of the car:

We will need a hole located in the bottom of the trunk to connect the socket to the rest of the wiring. In the case where the coupling device is made independently, you will have to drill the holes yourself. Consider the location of your future location;
After the socket is installed on the towbar, we will stretch the wire through the hole in the trunk and connect it to the socket.

The connection diagram for Largus can be of some help if you are the owner of this particular model

During connection, the wiring must be connected in such a way as not to confuse the order. If the number of wires does not match, purchase an adapter for the socket. A special tube into which you need to pass the assembled wiring kit will help protect the electrical package from external damage and short circuits;
Secure the wires to the trunk walls and carefully cover them with upholstery.
You can connect the trailer, check how high it is from the ground, and whether its brake lights, turn lights, and running lights are working.

The towbar can be installed on any car. Installation points are indicated in the product instructions

Electrical work

Electrical equipment for towbars is a different area than the manufacture of towbars. When choosing a device, select it in such a way that it does not cover the vehicle’s license plate. Sometimes you have to cut off part of the bumper for this purpose.

The opposite situation may also arise when there is no need for a coupling device. For example, the owner purchased a vehicle with a tow bar installed, but wants to remove it. In this case, you will need to work backwards to disconnect all the wiring that is assembled together.

In the same way as we connected the towbar socket, we will disconnect it in the same way.
Mechanically it can be dismantled using a special key.
If it is not there, then you will have to cut off the bolts or welds. It is better to entrust such work to experienced mechanics and electricians.

Which cars require a matching unit?

Determining if you need a towbar connection block is quite simple, just unscrew one of the car's headlight bulbs and see if any notifications appear on the car's dashboard. If no problems are identified, then most likely you can do without a smart connector.

Be sure to install the appropriate block in:

Audi - A3, A4 (since 2007), A5 (since 2007), A6 (since 2005), A7, Allroad, Q3 (since 2011), Q5 (since 2008), Q7 ( since 2006), TT.
BMW - Series 1 (F20/21) after 2011, 2 (E90/91) after 2005, 3 (F30) after 2012, 5 (E60/61) from 2003 to 2010, 5 (F10 /11) after 2010, 5 (Gran Turismo) after 2009, X1 (E84) after 2009, X3 (E83) from 2004 to 2010, X3 (F25) after 2010, X5 (E53) from 2000 to 2007 in America, X5 (E70) from 2007 to 2014, X6 (E71) after 2008.
Ford: B-Max after 2012, Explorer after 2011, C-Max/Grand after 2010, Focus 3 (2011+), Galaxy (2006+), Kuga (2012+), S-Max (2006 +), as well as Mondeo (2006+).
Mercedes - Class A, B (2004+), C from 2005 to 2014, Sprinter, GLK, Vito, Viano, W169, W204, S204, W245.
Opel - Adam (2013+), Agila, Astra (after 2004, except sedans), Corsa (2006+), Vectra (from 2002 to 2008), Zafira (2005+), Vectra C, Insignia, Adam (2013+) .
Renault - Sandero (2014+), Captur (2013+), Laguna (2007+), Laguna 2 (2014+), Fluence (2009+), Master (2010+), Megane (2008+) and Megane Grand Scenic launched after 2009.

This is not a complete list, but as you can see, most often the corresponding unit is required for cars manufactured after 2005 (except Volvo XC70 2000-2007). The smart connector is also installed in SUVs or crossovers. For example, a Duster towbar requires a corresponding unit, since it has a CAN bus installed, which takes care of the correct operation of all systems.

You may also need a smart connector if:

Your car has multiplex wiring.
The vehicle has a CAN BUS data transmission device.
The car is equipped with an automatic diagnostic system, Check Control.
The tow truck is equipped with an SLF system that scans the vehicle for burned out light bulbs.
LED car lighting.

To know for sure whether you need an additional module, it is best to check this information with your car dealer or do a simple experiment with a light bulb. However, if you have a car made before 2005, you may also need a smart plug.

Functions of the coordination block

The characteristics of the corresponding unit depend on the factory settings and capabilities. Key features include the following options:

trailer turn signals;
fog lamp control;
disabling parking sensors while using a trailer;
Charging the trailer battery.

Advanced versions may have the following parameters:

check the trailer connection status;
left side light control;
control of the left fog lamp;
aLARM-INFO anti-theft system.

Advantages and disadvantages of a homemade block

Whether it is necessary to buy a matching unit for a tow bar or make it yourself, everyone decides for themselves. If you don’t have the skills to work with electronics or even the concept of it, you shouldn’t start independent production. It’s better to spend money and buy a high-quality factory-assembled smart plug module.

Homemade trailer unit

The main advantage of home-made retrofitting is lower material costs for manufacturing the Smart Connect module than for purchasing it. Its disadvantages include:

simplified design that provides the minimum necessary functions;
complex installation - installation of harness connectors requires a box of complex shape, which will complicate the task of manufacturing the module, and many wires coming directly from the box create additional problems when connecting the unit;
less reliability, not all car owners have the skills to make printed circuit boards, and connecting diodes and relays to wires is fraught with short circuits if one of them breaks or the insulation is damaged, for example, due to overheating.

If you still decide to purchase a ready-made matching unit, then it is advisable to purchase high-quality products from the most reliable and reliable manufacturers, for example, the Bosal or Thule brands.

Why is BSF needed?

Many car manufacturers equip their models with on-board computers. Any attempt to connect the tow bar directly to the trailer will fail completely. The computer will bombard the unlucky driver with numerous errors, without seeing a new participant in the electrical circuit. The situation is corrected by a small Smart Connect device, which takes over control of the trailer.

Another reason for installing a towbar hitch assembly is the increased load on the vehicle’s standard system. Battery consumption also increases due to the need to power the trailer's dimensions, its turning lights and additional equipment. All together this leads to a short circuit and detonation of the entire car. The block will take on part of the load, and a short circuit will no longer threaten.

Quarantine will also prevent a complete collapse of the system, given the infrequent use of the trailer (commercial freight trains being the exception). Driving without a trailer will damage the power supply. And failure of the fuse in the absence of a towbar coordinator will cause a power failure for all elements. An emergency situation with expected consequences will occur during fog or night driving.

When connecting the towbar block, the following are adjusted:

Operation of on-board equipment.
Control of turn signals and trailer lights via the interior console.
Short circuit protection.
Ability to control the fog lights of the towed vehicle.

Signs to buy BSF are LED lights in the rear optics and a mention of the corresponding definitions in the car instructions. In the English version it could be SFL or Cumbus. A link to the need for a block may be in the on-board computer - the option to control external lighting. Also, an official dealer may insist on purchasing a matchmaker.

Purpose

The coordination unit for the towbar electrics is an unloading device that allows you to ensure uninterrupted operation of the vehicle and trailer electronics. The equipment protects the vehicle wiring from overloads - as a result, the vehicle’s on-board computer does not detect the connection of peripheral devices to the vehicle’s electrical network, and operates normally.

Operating principle of the equipment:

Smart Connect receives data from the on-board computer system.
The matching module provides a dosed and uniform load on the lighting equipment of a car trailer.

When installing a towbar, the electrical socket of the trailer and the BSF are connected in parallel using special clips.

Some car models have a trailer towing mode. In this case, it is not recommended to use universal BSF. The vehicle's electronic control unit (ECU) does not recognize the equipment and the option will stop working. To ensure the functioning of the trailer towing mode, the original BSF is used.

When is a module needed and on which cars is it installed?

Smart Connect is required if the vehicle is equipped with the following electronic systems:

on-board computer with CAN-BUS data transmission system;
Electronic AC voltage control function;
multiplex wiring in the car;
burnt out lamp detection system;
check the control system;
LED lighting and low voltage power supply.

Below is a table of car brands and their models in which the installation of the corresponding unit is required when connecting a trailer:

Car make	Model
BMW	X6, X5, X3, 1, 3, 5, 6, 7
Mercedes	The entire range since 2005
Audi	All roads, TT, A3, A4, A6, A8, Q7
Volkswagen	Passat 6, Amarok (2010), Golf 5 and Golf Plus (2005), Caddy New, Tiguan (2007), Jetta New, Touran, Toureg, T5
CITROEN	C4 Picasso, C3 Picasso, C-Crosser, C4 Grand Picasso, Berlingo, Jumper, C4, Jumpy
Ford	Galaxy, S-max, S-max, Mondeo
Peugeot	4007, 3008, 5008, boxer, partner, 508, 407, expert, beepper
Subaru	Inner Legacy (2009), Forester (2008)
Volvo	B70, C40, C30, C60, SS70, B50, SS90, SS60
Suzuki	Splash (2008)
Porsche Cayenne	since 2003
All terrain	Commander, Liberty, Grand Cherokee
KIA	Carnival, Sorento, Alma
Mazda	Mazda 6
Dodge	Nitro, Caliber
Fiat	Grande Punto, Ducato, Scudo, Linea
Opel	Zafira, Vectra C, Agila, Insignia, Astra H, Corsa
Land Rover	all Range Rover models since 2004, Freelander
Mitsubishi	The Outsider (2007)
Skoda	Yeti, Octavia 2, Fabia, Excellent
Seat	Leon, Alhambra, Toledo, Altea
Chrysler	Voyager, 300C, Sebring, PT Cruiser
Toyota	RAV-4 (2013)

How to make a smart connection with your own hands

In order to assemble a matching block for a towbar with your own hands and connect it, you will need the following parts:

construction cardboard;
about five diodes;
relay (number matches the number of diodes);
box in which the device will be placed.

Assembly diagram:

install diodes on the board;
install a control relay on the board;
Ready to install monitoring relay board
connect like this:
Connection diagram of the corresponding block
carefully pack in a box made of dielectric material.
The corresponding module must be placed in a dielectric box (box)

Making a smart connection with your own hands

To make a block diagram for a towbar with your own hands, you will need:

To pay. Diodes and relays will be installed later.
Diodes.
Relay.
Dielectric plastic housing for the device.

The smart connector is assembled as follows:

Diodes are installed on the board.
Next is the relay.
The wires are connected according to the diagram.
The equipment is housed in a housing.

The towbar hitch assembly can be purchased in the store - a factory-assembled accessory that is highly reliable, functional and of high quality. However, if you have skills in working with printed circuit boards, then this device can be assembled yourself.

Service

DIY car amplifier

Maintenance of the trailer hitch consists of periodic inspection, tightening of bolted connections, and checking the geometric parameters of the coupling ball.

The frequency of maintenance of the trailer hitch should be carried out in conjunction with the maintenance of the vehicle.

Let us remind you that we previously told you how you can make your own organizer in the trunk of a Lada Vesta.

Keywords: Lada Vesta accessories| Lada Vesta trunk

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