Tail lights

[Broncokid1984]

When I turn one of my turn signal on they both flash I checked the pig tail on my truck and only one side works at a time I've tried to chase the wires but can't figure out where the problem is.thanks in advance

 

[JackandJanet]

Hi Bronco - sounds like you may have an insulation break that crosses the two turn signal positive wires somewhere in the trailer? Do they both flash when you activate either the left or right turn signal?

I discovered an internal short in my trailer's plug before our last camping trip that would trip the trailer's battery box circuit breakers. I fixed it by replacing the plug with one I got from an AutoZone store.

If you have a binding post panel where the trailer cord wires are connected to the trailer wiring (mine's on the side of the battery box), you could check for a problem in the trailer cord. Disconnect both positive turn signal feeds from that panel and then test them with a voltmeter between each of them and a known ground as you activate the turn signals. If both are live, I'd suspect the plug is faulty. Alternatively, you could check for continuity between both of them with the trailer disconnected from the to vehicle, which would indicate a short. If the problem is not in the cord, test for continuity between the two wires in the trailer.

If the short is in the trailer, you'll probably have to run new wires, which could be a bit of a struggle.

- Jack