Troubleshooting Trailer Wiring Installation on a 2003 Honda Accord Wiring #118302

Question:

I just hooked up my wiring harness - everything hooked up great, and it didnt seem possible to mix any of the connectors up. However, when I put either my left signal or my right signal on, both the left and right trailer signal lights flash. They are powered by yellow/brown left and green/brown right.

asked by: Tim B

Expert Reply:

It sounds to me as if you have a problem with the trailer wiring.

I would start off checking all of my ground connections and tracing all the trailer wires to be sure none are broken or shorted. The first place I always look is where the license plate mounts with the taillight on the left side of the trailer. The lights are most likely grounded through the mounting connection to the frame and if the bracket is plastic it can sometimes interfere with the connection and cause problems. Make sure that the mounting brackets for the lights are connected to the trailer frame securely and are making good ground connection.

If the ground connections are not the problem and the trailer wiring is good, then I would disconnect the trailer and go to the converter and test the wires going in and coming out of the converter for proper function. If the wiring going into the converter is good and the wiring coming out is not functioning properly then the converter is most likely bad and will need to be replaced.

If the wiring going into the converter is not functioning properly I would check the connectors and make sure they are all connected properly and that the locking tabs are seated.

Finally if everything seems to check out, and the connector at the rear of the vehicle is functioning properly, the problem is in the trailer wiring and you will need to find a pinched broken or shorted wire.

expert reply by: Robert G