Right Brake Light and Turn Signal Not Working on Trailer Towed by a 2007 Toyota RAV4

Question:

Ive had this T-one connector installed on my 07 Rav4 Sport V6 for about 3 years now and all of a sudden my right brake and turn signal does not work. When I measure voltage on the 4-pole connector green wire, vehicle side, I get approx .20V when the brake is applied and the same alternating to 0V when signal is activated. If I jumper wire the yellow wire from the vehicle to the green wire on the trailer, the lights work so I know it is not the trailer wiring. All other connections work fine running lights, left brake, left signal. Please let me know how to troubleshoot since now I am simply looking at a black box for the t-one electronics.

asked by: Justin K

Expert Reply:

There is some testing you can do on the wiring harness for your 2007 Toyota RAV4. First, make sure that the converter box ground connection is intact and there is no corrosion. You can also try moving the ground.

To test the converter, use your meter to test the wires going into the converter. If all of the signals are coming through as they should, then you can move on to the next step. If they are not, that indicates an issue on the vehicle that will need to be addressed.

But if the signals are correct, test the wires coming out of the converter like you did before. If the signals are correct going in but not correct going out that indicates a problem with the internal circuitry of the converter and it will need to be replaced. I have included a video that may help with testing.

expert reply by: Michael H