Trailer light issue?

7-way light tester is good to have in general but are a great and easy diag tool for seeing if it's a tractor or trailer issue.

If you have a spare bullet light, use it as a test dummy. Unplug the cable from the trailer and stick one wire in the ground and the other in the right turn. If the light doesn't flash, it's either the cable or the truck, probably fuse. If it does work, it's a trailer issue.

 

short between green and brown wire, they dont flas cause voltage from brown wire is constant

 

Sounds like grounding issues. I agree with others, start at truck pigtail and work your way back to back of trailer.

 

I had a very similar issue yesterday. It was a broken wire on the back part of the trailer. Got mine fixed at the TA in Columbia NJ

 

This will get you home!!

 

I carry one of these. Super handy, with today’s CAN bus electrical systems.

https://a.co/d/46ofnQZ