Tow bar wiring
Of the many cars equipped with a tow bar, most likely have electrical “hidden” car tow components. This electrical installation is commonly referred to as “Bypass Electrical System”. This system is used to protect automobile lighting systems from possible damage in the event of a wiring malfunction in a trailer. It is a proven and widely used system. Bypass systems are found in both “universal” (non-vehicle specific) systems and dedicated and OEM systems.
Since the early 2000s, vehicle technology has advanced with the introduction of CANbus network systems that allowed the interaction of different systems and even the detection of a trailer or caravan. In some cases, manufacturers have not only designed cars to detect the presence of a trailer, but have also created new and improved functionality within grid-connected systems. This actually makes it important for these particular vehicles to be able to “see” the trailer or camper. Some of these new features are for safety and stability, but most are simply things of convenience, such as automatic shutdown of the rear fog lamp and parking sensors. The main safety innovation, now appearing in some cars, is the Trailer Stability Program, which is automatically activated when a trailer is detected on the network via dedicated sensors.
Some of the advanced systems introduced in some vehicles that can use trailer presence detection are: Lane Change Assist, Brake Electronics, Adaptive Cruise Control, Suspension System (ASS), Engine Electronics, Cooling System engine, parking aids and reversing camera.
The TSP or Trailer Stability Program is a feature that has been added to some vehicles to help correct the “snaking” action of a trailer. With such advanced technology, some brake systems have evolved even further and are operated electronically, without the need for hydraulic systems. Braking can become more controlled with faster braking efficiency when towing. Some suspension systems can now sense a trailer and allow a smoother trailer setting when load is applied to the tow bar. Adaptive Cruise Control (ACC) systems are designed to “detect” a trailer in order to create greater stopping distance between vehicles. It may be considered unwise to bypass the trailer detection systems of such vehicles, as these vehicles may be designed to behave differently when a trailer is placed.
Some manufacturers plug a prepared connector into the vehicle that is a network setup (Ford, Volvo) to accept a specially designed trailer module, or they have designed the trailer to be “ sensed ” through connections directly on the bus data (VAG, BMW). With these connections, the vehicle will know when a trailer plug is connected to the plug.
On vehicles that do not have safety features that rely on the vehicle to detect the presence of a trailer, bypass systems, properly installed by experienced installers, are highly efficient and cost-effective alternatives to expensive OEMs and other dedicated kits. . All bypass kits will be approved for use in vehicles (check mark (s)). They have the inherent advantage of completely isolating the trailer from the vehicle’s lighting system, thus protecting against damage to the car caused by faults within the trailer’s wiring. However, several manufacturers advise against making connections in the light wiring.