Troubleshooting Running Lights and Turn Signal Not Working When Both Powered on Trailer Right Side

Updated 06/14/2018 | Published 06/12/2018

Question:

I just installed a new wishbone harness 5 wire white is ground left signal and running lights work on the right side my right turn signal will work but as soon as I wire the right side running light wires I get nothing . I can have either running light or signal not both so I have a short on the right side wires somewhere

asked by: Paul

Expert Reply:

Since both the running lights and turn signal light on the right side of your trailer work fine independently, but not when both functions are activated at the same time; this actually makes me think that there is a ground issue. Most likely the bad/weak ground isn't with the new wishbone wiring you just installed, as that would likely cause this same issue on both the left and ride side. Since it is only on the left side tail light, I recommend checking the ground connection for the tail light assembly itself.

Your particular tail light may have a dedicated ground wire that gets attached to the trailer frame, or it might simply ground through its mounting hardware. In either case you will want to make sure that it is grounded to a clean, bare metal surface that is free of any debris or corrosion. Cleaning the ground surface should hopefully resolve the issue.

If you are still having trouble, please let me know and I will be happy to look into this further.

expert reply by: Chris R