Troubleshooting Turn Signals, Brake Lights Not Working with Running Lights On on a 2006 Silverado

Question:

My turn signals/ brake lights dont function when the headlights are on. When off they work fine. I have a 2006 silverado 1500 with the HD wiring package. not hd model of truck The 7 pin round is already on the tow hitch. there is however another blue wire labeled CHMSL. How would i go about resolving this problem? my trailer also has a 7 pin round. electric brakes. I do not have a brake controller and probably wont be buying one in the near future. i just would like to figure out my lights. also does the blue wire already in the 7 pin on both ends control the electric brakes?

asked by: Mike

Expert Reply:

It sounds as if you have a classic ground issue. When the vehicle running lights are on, and the brakes and or turn signals are activated, the amperage draw is the greatest and the faulty ground shows up. I would start with checking all of the ground connections on the trailer.

Check the ground connection at the coupler and make sure it is attached to a rust, corrosion and paint free part of the trailer frame. Next, check all of the trailer lights. Most trailer lights are grounded through the mounting hardware so make sure the mounting hardware to trailer frame connection is clean also. If any of the trailer lights have separate ground wires, check those also. This should solve the tail light issue.

The blue wire in the 7-Way is usually the wire that carries the brake signal to the trailer connector. I have linked an informational article that shows typical trailer wiring and the wiring details for the 7-Way connector for you to check out.

If you are thinking about a brake controller I would recommend the Tekonsha Prodigy P2 Proportional Brake Controller, item # 90885 and wiring harness # 3015-P, that is confirmed as a fit for your truck. I have posted some information on installation below for you to check out also.

expert reply by: Robert G