Troubleshooting Trailer Blinkers that Alternate when Blinker is On

Published 10/15/2015

Question:

hooked up new lights and mounted them...worked great before ...when my running lights are not on everything works good..I turn running lights on then I turn on a turn signal and the two lights on the trailer alternate blinking ..I turn running lights off one one blinks the side thats on ...grounds are all clean and tight to trailer

asked by: Barry

Expert Reply:

That is an interesting problem you are experiencing. First thing you want to do is test the 4-way that is installed on the 2004 Xterra for voltage on the correct pins with a circuit tester like # 3808 like the video I attached.

If the 4-way test fine then the problem is somewhere in the wiring of your trailer. Since the problem you described would be very difficult to manifest on trailer side wiring I would assume the problem is on the vehicle.

The harness wouldn't most likely be the root of the problem as it basically just connects to the vehicle. Most likely the problem would be related to the way your vehicle is wired.

I attached a help article on trailer wiring troubleshooting for you to check out as well.

expert reply by: Jameson C