Troubleshooting Trailer Lights on 2008 Dodge Grand Caravan with T-One Wiring Harness # 118552

Expert Reply:

If you ran the power wire and have current there, before the connector, then you will need to use a circuit tester, item # 3808 if needed, and check each one of the other circuits going into the converter. Make sure they are functioning properly. This should be done without the trailer connected. If they are not working properly check the connections behind the taillights and the ground connection to make sure they are secure.

If all connections before the converter are functioning properly, then check the trailer connector and see if the brake tail and turn signal lights are working properly. If not then the converter is either bad or has been shorted out.

If the trailer connector on the T-One Vehicle Wiring Harness, item # 118552, is good without the trailer hooked up then you will need to check the trailer for possible wiring problems. The most common situation is that there is a bad ground on the trailer. A bad ground on the trailer will cause the situation you are seeing. Check all of the ground connections on the trailer especially where the taillights are mounted to the trailer frame, and where the light brackets are mounted if they are bolted to the frame. If a plastic license plate holder is mounted between the left side taillight and the trailer frame this could be the problem. Once you have all of the ground connections checked if the problem persists you will need to check for a broken pinched or frayed wire on the trailer somewhere.

expert reply by: Bob G