Trailer Lights Stay On Bright When Connected to 2008 Toyota RAV4

Question:

Installed T-connector on 2008 Rav 4. The trailer lights come on with headlights - they come on in what appears to be fully lit Brake mode - no change in trailers light status with application of brakes, turn signals, etc.

asked by: Mike

Expert Reply:

This sounds like a ground issue. Ground issues can cause all sorts of weird things to occur on a trailer. The first thing you are going to want to do is disconnect the trailer and use a circuit tester like # PTW2979 if needed to test the 4-Way end on the RAV4. You will be testing to make sure you get the proper signals. If the signals are not correct on the 4-Way then check the ground and make sure it is attached to a clean bare metal surface. Moving the ground might also help.

If the problem still happens use the circuit tester to test the wires going into the converter box on the vehicle side. If the signals are not correct there then there is either a wiring problem on the vehicle or something has not been installed quite right. A bent pin in one of the T-connectors could also cause some issues.

If the signals are correct going into the box but wrong coming out then that indicates a problem in the converter and it will need to be replaced.

If everything checks out on the vehicle you can move on to the trailer. On the trailer make sure the connector is clean and free of corrosion. Check the main trailer connector ground and the grounds for each of the lights. They all need to be attached to clean and corrosion free bare metal surfaces. I have included a few links that should help you troubleshoot.

expert reply by: Michael H