Troubleshooting Trailer Turn Signals that Dont Flash When Brakes are Applied

Updated 02/13/2017 | Published 02/11/2017

Question:

the left and right signal ..both signals on the trailer flash. when holding the brake pedal on the truck......no turn signal at all

asked by: Joe

Expert Reply:

I would start by checking the trailer connector on the vehicle with a circuit tester like # PTW2993 to see if the issue is happening there or is it with the trailer wiring. If you're losing the turn signal function when the brakes are applied at the trailer connector, then the issue is on your tow vehicle. In which case I would have your vehicle checked by a mechanic.

If the trailer connector tests fine, then the issue is on the trailer. Check the ground connections for each light. Make sure they're grounded to a clean, bare metal surface. If there's no issue with the grounds check the lights wiring starting at the lights going towards the trailer connector. Look for any damage or pinch points.

If you still can't find the issue let me know and we'll continue to troubleshoot.

expert reply by: Charles S