Troubleshooting Right Signal Lights on Trailer Not Working

Question:

I have a 2006 GMC Sierra 1500. I went to rent a uhaul but when I hooked up the trailer only the right running light worked. Left turn signal, running light and brake light worked fine. The right however did not. The 4 ways did not work on the right side, the right blinker and brake light did not work. The uhaul rep tested my trailer receptical and said theres no power going to the right side of the trailer but all the lights on my truck work fine. Any advice?

asked by: Kevin

Expert Reply:

It sounds like there could be a ground issue somewhere on the trailer that is keeping the right signal lights from working properly.

Before checking the actual ground connections, I recommend first looking at both the vehicle and trailer side connectors. Check to make sure they are both free of dirt and corrosion, looking for any debris that might be preventing a solid connection. While there, you should also make sure they are both properly grounded.

It sounds like you may have already done this, but just in case you haven't, you should also test the vehicle side connector with a circuit tester like # PTW2993. Test the pins of the connector for the right turn and brake to see if it receives power when that function is activated in the vehicle. If you are getting power, then we know the issue is on the trailer side.

Going to the trailer, make sure the main ground is connected to a dirt and corrosion free bare metal surface on the frame. Also check the tail light assembly itself for any damaged/broken wires or loose connections. Typically trailer lights will ground through their mounting hardware, so make sure everything is securely connected.

If you are unable to find and resolve the issue, please let me know and I will be happy to look into this further. I have also attached a troubleshooting article that you might find helpful.

expert reply by: Chris R