Trailer Light Troubleshooting

Updated 07/02/2018 | Published 06/29/2018

Question:

Checked wires coming from truck only getting running lights. I grounded the white wire of truck to trailer frame connecter. To frame. I also grounded white wire of harness going to the rear to ground coming off trailer connecter also . still no rnning lights at rear of trailer which is rubber mounted and ground white wire of light to harness still no running light i just want running light for now untill i can rewire truck thanks.

asked by: Kenny

Expert Reply:

I don't really know what you're asking, but in order to determine the specific problem you'll need to use a circuit tester such as # PTW2993 to test the connector on your truck after disconnecting it from your trailer. Check the wiring going into your harness from your taillights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring. If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring.

Also, check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged. I've added links to a pair of help articles on trailer wiring that you may also find useful.

expert reply by: Kyle S