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Towbar Electrics options for CAN bus Vehicles.

Cars are becoming more and more complex and it is important that all work carried out on these modern vehicles is fit for purpose. Most modern vehicles have a CAN bus electrical system and you have a choice when fitting a Towbar to the vehicle as to what type of electrics you require. It is not possible on a CAN bus vehicle to connect the Towbar electrics directly to the vehicles lights. This will cause problems with the bulb failure monitoring system in the vehicle and also cause failures of the vehicles lighting control modules.

We aim to give you a simple explanation of the two options available from McCabe Towbars.

Bypass Relay System

  • As standard we fit an approved bypass relay system to these vehicles. This kit has a separate fuse for the 12 volt supply and only takes a signal from the cars harness to switch the built in relays in the module.
  • This kit does not affect the bulb failure monitoring in the car and it has a built in C2 Beeper to act as a bulb failure for the trailer when towing.
  • It has no option to switch off the reversing aids on the vehicle when towing but does not have a negative impact on them either.
  • The main thing with this kit is that it is invisible to the vehicles computers so the towing vehicle is unaware that it is towing.
  • On a lot of vehicles, the Vehicle Stability Control has a setting which performs slightly different when towing but this will not happen when a bypass kit is fitted.
  • This system is the most cost effective way of fitting towing electrics to a modern vehicle.

Vehicle Specific Wiring Kit

  • We do have an option of an ECS or Westfalia vehicle specific wiring kit which can be fitted to the vehicle making it visible to the towing Vehicle.
  • This is an option if required by the customer for most vehicles. They are more expensive and time consuming to fit but are more beneficial.
  • With these kits fitted, the reversing aid will switch off when a trailer is connected and the vehicles bulb failure monitoring system will be extended to the trailer also. A lot of manufacturers have the vehicles tow prepped and some will tow prep them if requested. If a vehicle is tow prepped it is a very simple job to plug in the kit. If not, it is a more difficult job to fit. Some models require additional coding from a main dealer after this kit is fitted.
  • The supplier of our Bypass Kit has recommended to us that their kit is not suitable for certain models, and on these models we supply only a Vehicle Specific Wiring kit.