I installed LED tail lights a few months ago, now all of a sudden the passenger side does not light for brakes or turn signals. The lights came with resistors that I put in when installing and the adhesive wore out and they were dangling in the truck frame. The wieres connecting the resistors to the light were damaged. I taped the exposed wires and secured them a with a heavier tape, but taping did not help. I also tried switching the resistor packs with the driver side to see if it was them that have an open winding, but they are still operable. I narrowed it down to wiring between the trailer hook up and passenger light assembly in the electrical circuit. I plugged an LED light bar into the trailer connection and the same problem occured(running lights come on, but no turn signal or brake light). Where could there be a short? Or is this circuit fused somewhere that the running lights come on but a separate fused circuit triggers the higher voltage for LEDs. Any input definitly appreciated, thanks.

 

What kind of vehicle?

 

2011 f150 platinum with the 3.5 ecoboost... I checked all the fuses, and the relays for the right turn signal and brake. Nothing is blown or shorted there.

 

Check Fuse 13 (15 amp) in the Body Control Module (BCM). Power to the RR Stop/Turn light is switched by a transistor in the BCM. Check power and ground at the bulb to ensure you have a good circuit. Power is a violet wire w/ orange tracer and ground is a black wire.

 

the fuse at 13 is ok, switched with 15 (fuse for left side stop/turn) and same issue occured. Where is the transistor? Is it in the same fuse panel on the passenger side?

 

The transistor is internal to the BCM. It is not field servicable. Check your power and ground at the bulb.

 

If the fuse is on the output to the brake turn from the body module, I would go buy a testlight at the store, and then with everything on and blinking, probe the fuse. The testlight should blink. If it does, then you still have a wiring problem somewhere at the rear. If it doesn't, the body module must be blown. You should be able to switch the turnsignal from side to side and compare the results.

 

The fuse is before the transistor. You can backprobe the VIO/ORG wire
coming out of the BCM or backprobe the same wire going into the
Battery Junction Box (BJB). You can also pull your Right Turn Trailer Tow Relay
and probe for power on terminal 1. All this testing is done with your turn signals on of course.

 

No power to the light when signal is turned on. Fuse is not blown. I'm guessing a wiring problem somewhere between the light and fuse?

 

You will need to get a testlight and go up to the body module like the previous post mentioned.