Troubleshooting Left Turn Signal Not Working After Installing Curt T-Connector 4-Way Harness

Question:

I have installed the wiring harness 56094. Simple installation however the left turn signal is not working. I have gone back and checked all the connections and they seem fine. I sanded the area around the ground for a better contact but it did not solve the problem. All of the car lights and signals work. Your thoughts.

asked by: G B

Expert Reply:

I first recommend using a circuit tester like # PTW2993 to test the left turn signal/brake light pin on the newly installed 4-Way. You can have a buddy activate the function in the vehicle while you test the pin for power. If you get appropriate power at this pin, then the issue is actually on the trailer side and you will want to turn your attention there.

On the trailer, check its 4-Way for any corrosion or debris built up inside the pins, cleaning as needed. Make sure the main ground is securely attached to a clean bare metal surface. Also check the left side light assembly itself on the trailer to make sure it is securely grounded, whether it grounds through a dedicated ground wire or through its mounting hardware.

If you didn't get power at the 4-Way when testing it then the issue is indeed somewhere on the tow vehicle and T-Connector harness. It seems that you have already done a lot of troubleshooting on this side of the equation. Since you have already made sure the connections are secure and verified a clean and secure grounding location, I recommend testing the left turn signal wire going into the 4-Way (yellow wire). See if you get power there, which may indicate that the 4-Way connector itself is bad.

Please let me know if you are still unable to find and resolve the issue and I will be happy to look into this further.

expert reply by: Chris R