Troubleshooting Running Light On Trailer Hooked Up To 2007 Toyota RAV4

Question:

I own a RAV4 and purchased a towing wiring harness several years ago. Recently, my trailer driver side light goes on bright and stays bright when it should be off, including when the vehicle is turned off. I have to unplug it to turn the light off. Is there any repair? Thank you.

asked by: Gordon S

Expert Reply:

Since you said recently this problem has been happening, I suspect the problem may be as simple as a loose ground wire or one that has a short. I would first check all of the wire connections on the trailer to make sure there is no build-up of corrosion or a broken wire. If everything checks out okay, I would unplug the harness from the vehicle and using a circuit tester like part # PTW2993, check all of the pins on the vehicle harness for function to see if there is an issue on the vehicle side.

If you have a powered converter, it is not unusual to have a small amount of voltage on the output side, but it should not be allowing full voltage to go through when turned off. If so, then the converter is bad and will need to be replaced. I have included a link to a video that shows how to test a converter.

If you find that you need to replace your vehicle side harness I recommend the Curt Custom Fit Vehicle Wiring, part # C56165. This is a T-One connector and installs easily by plugging directly into your vehicle wiring.

When working with wiring connectors, I recommend using dielectric grease like part # 11755. this keeps dirt and moisture out of the electrical connections and helps prevent corrosion.

I have included links to a couple of helpful articles you can check out.