Solution for Trailer Lighting Circuits that Have the Brightness Switched

Question:

I’ve re wired my trailer with a 4 pin LED kit. Wishbone wiring. With the headlights OFF, the blinker and brake lights left and right operate as expected but in the dim setting. With the headlights ON, the left and right taillights are in the BRIGHT setting. When the blinker is applied or the brakes are applied they do NOTHING, except maintain their brightness. The side marker to the taillight and the license plate light will brighten as if it were a brake or blinker. My first thought was that the running light plug was wired to the brake lights and viceversa. But with the trailer separated from the vehicle, I applied a 12v power supply to each pin of the plug and the trailer performed as expected. With a voltmeter, I checked the pins from my trailer hitch. I received 12v as expected, 12v with brakes and blinkers, 12 v with running lights, all with the corresponding pin. My grounds are connected to the trailer and are both operating. Need help.

asked by: David L

Expert Reply:

You have the circuits backwards on the taillight assemblies. Try switching the two circuits you have for each light assembly that have the stop/turn and the running light and you'll see the circuits work like they should.

expert reply by: Jameson C