No 12 Volt Power At 7-Way on 2008 Chevrolet Silverado To Charge Trailer Breakaway Battery

Expert Reply:

On a factory 7-Way connector the 12 volt hot wire should be the terminal at the 1 oclock position, looking at the front of the connector. If you test that terminal with a circuit tester and have no power you will want to check under the hood of your 2008 Chevrolet Silverado.

You will want to locate the power distribution box on the drivers side of the engine bay. Remove the cover on the distribution box. There will be two post terminals at the front of the box. The right post terminal is the power post for the 7-Way connector at the rear of your truck. It should have a wire running to it that comes from under the power brake booster. Also check the power distribution box for a 40 amp fuse that will activate the 12 volt power lead to the 7-Way. The location of that fuse should be identified on the inside of the power distribution box cover.

If the wire is not connected to the right post terminal you will need to find the wire under the power brake booster. It will have a ring terminal on the end of the wire. It is normally taped to another wiring harness. You will need to cut the tape and release the power wire from the harness. Then, run the wire to the front of the power distribution box and hook the ring on the right post and secure with a M8 nut, like the # 185917. Then, check to make sure there is a good 40 amp fuse in the correct slot of the power distribution box.

I am including a link to a FAQ page that will show the connections that need to be made on your vehicle. Also, I am including a link to a video that will show those connections being made on a 2008 GMC Sierra.

Remember, when using the 7-way for charging of the trailer breakaway battery that it can only maintain a charge in the battery.It will not charge the battery from a discharged state.

expert reply by: Jeff D