Curt Trailer Wiring Harness for a 2012 Toyota RAV4 Works with Test Light But Not with Trailer

Question:

I just installed the Curt 56165 when I put a light tester on the plug everything works fine left right and running lights When I plug it into my trailer I get NOTHING Now when I plug my suburban into the trailer everything works fine. Is the power module so smart its detecting a ground fault in the trailer?

asked by: Gabe O

Expert Reply:

This is an interesting problem since the trailer works with another vehicle and the harness works when you test it. It could be a ground issue somewhere. Plug in the trailer and then test the wires on the trailer side behind the trailer connector. If the signals are not getting further than the vehicle side connector then there is some issue on the trailer.

Make sure the main trailer connector ground and the grounds for all the lights are connected to clean and bare metal surfaces. If the trailer has an aluminum frame, a tilt bed, or folding then running jumper ground wires from the lights to the main trailer connector ground will help.

If you have access to another trailer, try plugging it into the Curt harness to see if it does the same thing. If it does then there must be an issue inside the converter and it will need to be replaced. I have included a link to an FAQ article that can help with troubleshooting.

expert reply by: Michael H