10 (ten) x Smart 7 way Bypass Relay, suitable for all multiplexed/CAN bus cars. Exceptionally low power, with built-in indicator Tell-Tale sounder.

Installation instruction included in the package. Dimensions: (excluding the wires) L. 100 mm - W. 46 mm - H. 29 mm.

The Smart Logic Module is a 7 Way Bypass relay, designed to work with all negative Earth modern cars (12V system).  Using uA Technology, the units has extremely Low power consumption (only 0.0001 Amp, or 100 micro Amp), which ensures it has no impact on the car battery. 

The robust relays provide power to the trailer lamps, from the separate 12V supply. As such the car wiring loom is fully protected and isolated from the trailer wiring (car loom cannot be overloaded or interfered with).

The Smart Logic Bypass is the perfect choice for all modern cars as well the older ones. It can work with multiplexed car lighting, as well as multifunctional bulbs such as combined Tail/Brake or Tail/Fog lights. Correct functionality and without any relay chatter.

Example 1: Combined Tail and Brake lights. 

Connecting only the Red wire to this circuit, is correctly decoded; hence when the bulb is acting as Tail, only the Trailer Tails is activated and when it is activated as Break, then only the Trailer Brake is activated. More importantly whilst this bulb is multiplexed as Tail and then Brake are applied, then both Trailer Tail and Break lights are both activated.

Example 2:  Combined Tail and Fog.

Connecting only the Blue wire to this circuit correctly decodes and manages the trailer Tail and Fog relays. Hence when this car bulb is behaving as Tail light, then the only the Trailer Tail is activated. When this bulb is multiplexed as Fog light, then both trailer Tail and Fog lights are activated.

Note: the Black and Brown (Tails) can also be connected to the car loom if dedicated Tail lamps are used, otherwise they be left out.


The unit has a built in audible indicator bulb failure (Tell Tail) function, which can also operate an external sounder/LED through the C2 terminal. With the trailer connected, it will beep in harmony with the flashing indicator.  A no beep highlights bulb failure or trailer disconnection. This function is mandatory part of MOT testing. 

Note: For optional remote sounder/LED, connect the +ve side to the +12 terminal and the –ve side to the C2 output terminal.


It will be dispatched with in two working days through eBay Shutl service. Faster delivery can be arranged at extra cost. Please contact for details.