Troubleshooting Brake Light/Blinker that Will Not Go Off Once Used on a 2008 Toyota Rav4

Question:

Good afternoon, I have installed a t-connect wiring kit to my 2008 Toyota Rav4. It seemed to be working fine until last winter. I havent used a trailer much since. When I plug the trailer or test light to my Rav4 the right brake light turns on and it remains lit until I remove the fuse from the engine compartment. When I put the fuse back in, everything seems fine until I engage the brake lights or the turn signal. Then the light stays lit until I remove the fuse again. It only does that on the right brake light. The left one works just fine. Ive checked the wires and they are still like new. I have drilled a self tap screw into the chassis to hook up my ground wire. Could a faulty ground do this? Help ? Please? = Thanks,

asked by: Matt

Expert Reply:

The first thing I would test would be the converter box of your trailer wiring harness. To do this you will want to use a Circuit Tester Kit # PTW2993 to test for voltage coming into the box and then for voltage on the corresponding output circuit side of the box.

For example, you will want to test for voltage on the right brake light circuit. You would do this by putting on the right blinker and then testing the input wire of the box for the right blinker for intermittent voltage. If you find that the voltage, there is blinking but then the voltage on the output side of the box is constant then you know the problem is in the box and it should be replaced.

Also, a ground problem could cause the issue you are seeing. Ground issues cause all sorts of bizarre taillight behaviors including what you are describing. After you test the converter box, I would recommend checking the trailer connector of your vehicle and trailer looking for any corrosion, exposed wires or anything else that might cause a ground problem.

Next, you will want to move onto the trailer looking for corrosion, exposed wires or cut wires on the right blinker circuit and fix as necessary.

I attached installation instructions and an installation video for the # 118412 for you to review also.

I attached an FAQ article on trailer wiring for you to check out also.