Troubleshooting Trailer with Turn Signals on Both Sides Flashing

Question:

I have checked the ground to the trailer and it appears ok I replaced the old trailer wire harness it is a four pin wishbone same as what was there before but now when I turn tail lights on the lights work fine but if I turn the turn signals on neither work but when I turn the tail lights off both sides blink wether I turn the right or left signals on I do not see ground wires at the light. I am stuck I have a tester that plugs into the four pin and it has led lights they all work correctly so I think its the trailer lights any ideas would be greatly appreciated!!!

asked by: Mike

Expert Reply:

As you seem to have already learned this is typically a ground issue. Since the lights themselves do not have a ground wire it means they're grounded through the mounting hardware. Start by making sure the hardware is good and clean and fastened to a bare metal surface. The mounting brackets, hardware, and the location they're mounted to need to be treated in the same fashion a ground wire's connection does.

If this isn't your issue let me know and we'll continue to troubleshoot.

expert reply by: Charles S