Trailer Brake Lights Not Working when Connected to a 2006 Toyota Sienna

Question:

Hello, Ive had this item installed for probably 5 years on an 06 Sienna and now the trailer right brake light is not working. All other lights work ok including the turn signals. The brake light is working on the van, all connections/wires look good. Does this indicate a problem with the converter? It seems to be where the problem starts. Thank you!

asked by: Mark T

Expert Reply:

You can test trailer wiring harness # 118304 to determine if it is the problem or if the issue is somewhere else. You can use a circuit tester such as # PTW2993 or a meter if you have one to perform this test.

Have someone sit in the vehicle and press the brake pedal. At the same time test the pins on the 4-Way, specifically the 2 that are the furthest from the exposed ground pin. If you are not getting power there when the brake pedal is pressed, then make sure your stoplight/CHMSL fuses are good. If they are, then the issue is likely the converter and the whole harness will need to be replaced.

If there is power when there is supposed to be then the issue is likely on the trailer side, likely a bad ground or corroded trailer connector. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light but can show up any time.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

expert reply by: Michael H