Troubleshooting Trailer Brake Lights Not Working

Question:

I just installed the hitch on my NX200t and everything was working fine until yesterday I took out the trailer out and noticed my brake lights were not working on the trailer. Everything else works, from backing up to the turn signals and even the driving lights but when I press the brakes they wont get bright. What can cause this issue?

asked by: Mario P

Expert Reply:

I would start by testing the trailer wiring harness, # 118652, you just installed on your 2017 Lexus NX200t. Use a circuit tester like # 3808 and test each function. If the problem is on the vehicle then check for any fuses related to trailer brake lights. If it's not a fuse you'll need to check the wiring connections you made when installing the harness.

If everything checks out at the 4-way trailer connector then the problem is on the trailer. Inspect the trailer's 4-way and make sure it's clean. The inspect the wiring from the connector back to the lights looking for any damage.

If after this you still can't find the problem let me know and we'll keep troubleshooting.

expert reply by: Charles S