Trailer Wires Got Severed Now 2009 Toyota RAV4 Wiring Harness Has Constant Power

Question:

I purchased the 118412 wiring harness for my 2009 RAV 4, installed it per the instructions and it worked great, until the wires on my trailer got severed. I repaired the wires and changed the 118412s 10amp fuse, but now the trailer running light stay on even when the vehicle is turned off and the lights are turned off. Also, the right tun signal on the trailer does not light up. The problem seems to be in the electronic module of the 118412 because, when I check the signal at the vehicle, its not getting power for the turn signal. What do you suggest?

asked by: Dale P

Expert Reply:

It sounds like the severed wires caused a big short circuit that damaged the guts of the converter box. These boxes are sensitive so they can protect the vehicle wiring in situations just like this. So it sounds as if it has done its job of protecting the vehicle. What you will need to do now is give the old harness a proper burial and replace it. You can go with the same harness # 118412, or another harness, see link.

Since you have already tested the harness it does not seem likely that there is another issue other than a bad converter due to a short. But you can find out by testing the wires leading into the box from the vehicle. If the turn signal is not working on the wire going into the converter then that indicates a problem on the vehicle, possibly a blown turn signal fuse.

The lights staying on could be a bad ground or corrosion in the trailer connectors. All corrosion should be cleaned off and grounds on the converter and trailer should be attached to clean and corrosion free bare metal surfaces.

expert reply by: Michael H