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AB Tools Towbar Electrics 7 Way Bypass Relay for Canbus Multiplex Wiring Smart TR186

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$38.50

$ 18 .99 $18.99

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About this item

  • The 12v supply should be fused at 15A
  • The smart relay will sense the input and output
  • this latest relay draws only 0.001A (1ma)
  • Easy to wire
  • Provides audible warning buzzer


This latest smart relay is designed to work on all cars with a negative earth system.
Easy to wire if you can wire a tow bar to the back of the lights like on older vehicles, with this relay you can wire up even the most advanced modern car.
Totally protects the cars wiring and control module from faults in the trailer, short circuits in the trailer, extra load etc.
The wires from the relay are connected directly to the back of the vehicle lights as with normal tow bar wiring to provide a signal to the relay. The relay then provides outputs to the trailer/caravan lights powered directly from the battery.
Because the lights are powered from the battery, this latest relay draws only 0.001A (1ma) from the vehicles lighting system, which will not effect any bulb warning system or vehicle wiring on even the very latest vehicles.
Will suit vehicles where the sidelights are powered from the same wire as the brake lights or fog lights (see wiring guide below).
Provides audible warning buzzer for trailer light operation (now tested in MOT's).
Wiring Guide
The wires from the relay should be connected;
Yellow Wire to Left hand Vehicle Indicator.
Blue Wire to Vehicle Fog Light.
White Wire to Vehicle Earth/Chassis.
Green Wire to Right hand Vehicle Indicator.
Brown Wire to Right hand Vehicle Side /Tail light.
Red Wire to Vehicle Brake Lights.
Black Wire to Left hand Vehicle Side / Tail light.
Grey Wire to Vehicle Reverse Light.
On the Relay connect the terminals as follows;
Relay Terminal 1 To Trailer Left Hand Indicator. (Pin 1 in tow ball socket)
Relay Terminal 2 To Trailer Fog Light. (Pin 2 in tow ball socket)
Relay Terminal 4 To Trailer Right Hand Indicator. (Pin 4 in tow ball socket)


R. S.
2025-03-22 16:45:58
Works but no documentation with the product and what you can find online is limited at best. Specifically, it will not work for trailer lights which combine turn signals and brake lights which is true for most small utility trailers. You can make it work with a couple of high Amp diodes. There are terminals and features which have no description or explication. I reached out the the seller and did not get a response. With some decent documentation and some customer support this could be a recommended product but as it is, only buy it if you have a clear understanding of electronics and don’t mind experimenting to discover how it is supposed to work.
Billy Bob
2025-01-28 21:08:51
Used for USA 7 wire setup with common brake signal wire and canbus. Used in 2016 Jeep Renegade. Relay clicking not too loud.
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