Troubleshooting Right Turn Signal Circuit Always Active on Vehicles Trailer Wiring

Question:

2003 silverado 2500hd factory harness. trailer has 12 v on rt turn wire as well as 12v hot lead on 7 pin harness. when trailer is hooked up running lights are all ok, rt turn works, left turn operated both and only left brake light illuminates but right running lights still on. checked pigtail from hitch connection and still have 12v on rt turn. traced wiring back to factory camper harnessbetween bed and cab and have 12v on rt turn still. all fuses ok. cleaned and inspected ground wiresboth on drivers side, one between cab and bed and other under drivers door. pulled fuses for trailer turn signals in fuse box and was able to verify no voltage at 7 pin connection.

asked by: Ryan

Expert Reply:

If I am understanding you correctly it sounds like you have 12 volts on the right turn signal at all times. And that you even tested the wiring of your truck further and further up the vehicle's wiring and still there was voltage on the circuit.

This to me sounds like a bad relay. A bad fuse would cause the circuit to stop functioning all together, but a bad relay will potentially cause a circuit to be active at the wrong time.

Check under the hood of your 2003 Silverado looking for all towing related relays and check as needed. The easiest way to test a relay is to insert a known working relay into the slot. If the circuit then starts to work correctly you know the relay you pulled is bad.

expert reply by: Jameson C