No Power On 12 Volt Circuit on 7-Way Trailer Connector on a 2006 GMC Sierra 2500HD

Updated 10/28/2014 | Published 10/27/2014

Question:

You addressed this question asked by Keith. I have a 2006 GMC Sierra 2500 HD with a Duramax Diesel and an Allison transmission. All running lights are functioning and the 12 volt accessory lead becomes hot when the ignition is turned on however I have no power to the 12 volt battery lead which should remain hot at all times correct?

asked by: Kenny

Expert Reply:

On some GM trucks, even those with factory tow package, the wiring is not always complete. You may need to manually run a wire from the front of the truck to the back of the 7-Way. I have included a link to the right that should help. It talks about the under the hood connections that might need to be made when installing a brake controller but also mentions the 12 volt power wire.

Presumably, if the wire is attached directly the positive terminal, it would have power all the time. But if it is connected via the fuse block then the truck would likely have to be on for it to be live.

expert reply by: Michael H