Trailer Turn Signals Do Not Blink In Tandem with the Vehicle Turn Signals

Question:

when brakes are being used the car turn and the turn for the grote-65720 led towing light are not flashing at the same time the two lights alternate flashing. otherwise the tow lights work fine. the mechanic that installed the T-connector said that was normal? if i have to purchase a new #56254 and start over i will. at another shop.

asked by: John M

Helpful Expert Reply:

Usually when towing a trailer, the turn signals will blink together with the tow vehicle and not alternate like what you are describing. So, I would say what you are experiencing is not normal. It is hard to say if it is a problem with the trailer wiring harness # C56254 or something that went wrong during the installation process.

I would make sure that all of the grounds are attached to clean and corrosion free bare metal surfaces. I also recommend checking the trailer side connector to make sure it is clean and free of corrosion. Ground issues can cause weird things to happen so it wouldn't hurt to double check.

You can also test the wiring harness using a circuit tester such as # PTW2993. What you will do is turn on a blinker (no trailer connected) and then test the associated pin on the 4-Way for that blinker. If the test light lights up in tandem with the car's blinker and does not alternate, then there is an issue on the trailer.

If it does alternate then check the input wire going into the converter box (yellow is left, green is right) and if that signal alternates, then it isn't the harness, just a strange occurrence with the vehicle wiring. But my guess is that if it is a problem on the vehicle side it would be inside the converter and it would need to be replaced.

expert reply by: Michael H