Connecting the towbar coordination block with your own hands

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.

Why do you need a coordination unit for towbar electrics?

Modern cars are increasingly equipped with new electronic systems to improve driver comfort and safety (ABS, TSP, ESP, etc.).
However, a huge number of wires are required to connect all these devices. To solve this problem, manufacturers use the CAN-BUS system - all signals go through just 2 wires. And when it is necessary to select the necessary signals, manufacturers install a decoding unit, from which wires go directly to consumers: to the brake system lights, fog lights, side lights, turn signals. With such a power supply circuit, connecting the electrical equipment of the towbar to the corresponding light bulbs of the car will naturally cause a change in resistance in the electrical circuit, which is recorded by the Check Control and burnt-out lamp detection systems, and leads to blocking of the corresponding circuit. In addition, in this case, the connected towbar lights may not work correctly: when the turn signal is turned on, the brake light comes on, for example.

To prevent this from happening, it is necessary to install a matching unit (Smart Connect), which is connected via a separate wire to the car’s 12V and does not cause a change in the load in the car’s electrical circuit.

What is Smart Connect

Modern cars are equipped with various electronic systems for greater comfort and convenience. To coordinate all these systems would require a huge number of wires. To solve this problem, automakers use CAN-BUS or CAN bus. The signals flow through only two wires, distributed through the bus interfaces. Thus, they are distributed to different consumers, including side lights, brake lights, turn signals, and so on.

Matching block

If you connect the electrical equipment of the towbar with such a system, then the resistance in the electrical network will immediately change. The OBD-II system will indicate the error and the corresponding circuit. Other lights may also not work properly.

To prevent this from happening, Smart Connect is installed. To connect, a separate wire 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.

On which cars should a matching unit be installed?

The matching module must be installed on vehicles equipped with the following systems: 1. Electronic control system with variable voltage. 2.Car with multiplex wiring. 3. CAN BUS data system (with on-board computer) 4. CHECK CONTROL system 5. Burnt out lamp detection system (SFL) 6. Low voltage lighting power system. 7.LED lighting system.

In vehicles equipped with such systems, directly connecting a conventional socket to the trailer hitch will damage the vehicle. Installing a smart connect module eliminates additional load on the vehicle's electrical network and stabilizes the network voltage. The connector is resistant to voltage surges and short circuits, as it connects directly to the car battery through a 15 A fuse.

The matching block also provides:

• switching the fog lamp to the trailer;
• control of direction indicators on the trailer;
• o turning off the parking sensors when attaching a trailer;
• charging the battery on the trailer.

Coordination modules with advanced capabilities have a number of additional functions: – trailer connection test; – PARK SENSOR; – ALARM INFO; – control function of the left side lamp; – coordination function of the left fog lamp.

• Trailer connection test - checking the condition of the electrical equipment of the trailer: after connecting it, all the lights light up one by one and you can make sure that everything is in order.
• The Park Sensor function is designed to block the parking sensors of a car with the Parktronic system, since when reversing, the trailer is perceived as an obstacle.
• The Alarm Info function provides the ability to connect a trailer to a car alarm system to protect it from theft. In security mode, when the trailer is disconnected from the vehicle, an alarm is triggered.
• The left side lamp control function is designed for a single-filament lamp, which simultaneously performs the functions of side and fog lights, as well as side and brake lights.
• Left fog light control is a function that allows you to adjust the intensity of the fog lights and prevent the driver from being blinded by the light reflected from the front of the trailer.

The matching module is required to be used on:

1. Audi: A4, A3, A6, A8, Q7, TT, Allroad.
2. BMW: 1, 3, 5, 6, 7, x3, x5, x6.
3. Chrysler: 300C, Sebring, PT Cruiser, Voyager.
4. CITROEN: C3 Picasso, C4, C4 Picasso, C4 Grand Picasso, C5, Berlingo, C-Crosser, Jumper, Jumpy.
5. Dodge: Caliber, Nitro.
6. Fiat: Ducato, Linea, Grande Punto, Scudo.
7. Ford: C-max, S-max, Galaxy, Mondeo.
8. Jeep: Grand Cherokee, Commander, Liberty.
9. KIA: Sorento, Soul, Carnival.
10. Land Rover: Freelander, Range Rover since 2004 all models.
11. Mazda 6.
12. Mercedes: all models since 2005 (GLK, Sprinter, W164, W169, W212, W203, S203, W204, S204, W211, S211, W245, Viano, Vito).
13. Mitsubishi Outlander since 2007.
14. Opel: Agila, Astra H, Vectra C, Zafira, Corsa, Insignia.
15. Peugeot: 3008, 407, 4007, 508, 5008, Bipper, Boxer, Expert, Partner.
16. Porsche Cayenne since 2003
17. Seat: Alhambra, Altea, Leon, Toledo.
18. Skoda: Fabia, Octavia 2, Superb, Yeti.
19. Subaru: Forester since 2008, Legacy Outback since 2009.
20. Suzuki Splash since 2008.
21. Toyota RAV-4 from 2013.
22. Volkswagen: Amarok since 2010, Caddy new, Passat 6, Golf 5, Golf Plus since 2005, Jetta new, T5, Tiguan since 2007, Toureg, Touran.
23. Volvo: C30, S40, S60, V70, V50, XC70, S80, XC60, XC90.

and some other models.

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: Do-it-yourself car battery maintenance, how to maintain it before winter and how to service a new battery, instructions with video

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.

Universal electrical kit – UniKit

Modules of the Unikit (Baltex) 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.

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Introduction to the essence of the problem