2003 Chevrolet Silverado Trailer Lights Go Out When Tail Lights are Turned On

Question:

I have a 2003 Silverado 1500. The brake, turn lights work on my trailer until I turn the headlights on...then nothing works. I use a 7 pin flat connector with a 7 pin/4 pin adapter. Connections look good. Checked what I thought were all the trailer fuses. Ill find it sooner or later, but Im hoping you have an easy answer. Thanks much! This page is very useful also. Good

asked by: Korey K

Expert Reply:

It sounds like you have a bad ground on the trailer. If all ground connections are not making good contact to bare metal when the tail lights are turned on and max amperage draw is applied, the trailer lights will go out or not function properly.

You will need to check all of the ground connections 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. Also, check the ground wire connection at the trailer tongue.

Once you have all of ground connections checked, if the problem persists, you will need to check for a broken pinched or frayed wire on the trailer somewhere. If this is not the case then you will need to use a circuit tester, item # PTW2993 if needed, and make sure your wire connections have been properly made at the taillights. You should also check the vehicle and trailer connectors for corrosion that can sometimes cause issues with the trailer lighting. If you look into the connector and see green corrosion you will need to clean out the connector.

expert reply by: Robert G