Thread: EBC wiring issue

The other month I purchased the Tekonsha P3 Brake Controlelr. I've got around to fully installing it at last and something strange has started to happen since I wired it to pin 5 of the trailer socket. Yesterday I'd wired it in to the vehicle, but I hadn't connected the last wire to the trailer socket.

The unit stays powered on until it receives no activity for 15 minutes. It then goes to sleep. This happened yesterday when the trailer brake wire wasn't connected to the trailer socket. Now it no longer goes to sleep.

When I check the voltage between the earth (pin 3) and the brake (pin 5) on the trailer socket I register 0.04V with almost zero current. This is confirmed on the P3 display which shows 0.04V and 0.00 as current. Interestingly the P3 display shows the voltage fluctuating between 0.04V and 0.07V, but the mutlimeter at the socket shows a steady 0.04V.

I have it wired as per instructions:
Red to brake peddle switch (cold side - GP wire on the 03MY D2)
White (-ve) and black (+ve) direct to battery with a 20A circuit breaker on the black wire.
Blue direct to rear of vehicle and pin 5 of trailer socket

Obviously it isn't going to sleep as it still has a small trickle of power going through it. I'm at a bit of a loss as to why this is occurring and thought someone might be able to shed some light. There's no change in the output voltage or current at pin 5 when any of the other circuits (indicators, lights, reverse) are activated. Pin 5 shows a higher voltage when the brake peddle is applied as expected. So I'm thinking its not a short at the socket, but I'm at a loss as to what it could be.

I have no way of checking operation of the P3 with a trailer connected until I pick up my camper trailer next month.

In the meantime I'll leave the unit unplugged. Although it's hardly going to flatten the battery quickly at if the current being used is only just registering at 3 decimal places.

Out playing with the mulitmeter again and have rewired the trailer socket. If the P3 isn't plugged in there is no problems at the rear socket (ignition on or off). When I plug the P3 in a get a 0.04V to 0.07V fluctuation on the P3's display for Stoplight and a constant 0.04V reading at pin 5 (brake) on the trailer socket. The brake output from the P3 (brake) shows 0.00V and 0.00A unless I either press the brake peddle or move the lever, at that put the display shows 6.00V (as set) and pin5 also shows 6V.

The only thing I can think is brake peddle switch is somehow involved and I'm wondering if I should put an inline diode on this wire to the Tekonsha.