How to Connect the 12 Volt Power Lead to a 7-Way Connector on a 2004 Chevrolet Silverado

Question:

the battery charge lead 1: oclock on my recently installed 7-way trailer connector is dead. I want to be able to maintain charge to my trailer battery. I saw a thread here regarding an 08 silverado where theres a taped wired on the harness to be connected to one of the posts just underneath of the underhood fuse box. But when I looked at mine, I could not find the taped wire nor the stud just under the fuse box. What do I need to do to get this lead on the 7-way 12v live and be able to maintain charge to my trailer battery. Help please

asked by: Ricardo S

Expert Reply:

If your truck did not come with a factory installed 7-way trailer connector, then there is probably no 12 volt power lead connected to the 7-way. The wires that you mentioned for the 2008 Silverado will not be present on your 2004 Silverado. GM changed the tow package wiring after 2006 on their trucks and SUVs, so if your truck came with a tow package and a 7-way connector, the 12 volt power lead should already be hot. Since it is not hot, it will need to be hard wired.

To complete this connection, you will want to run a length of 10 gauge wire, # 10-1-1, from the 7-way connector to the engine compartment. There are two ways for you to connect this wire. One method is to attach the wire to the positive terminal of the vehicle battery via a 40 amp circuit breaker, # 9510.

The second method is to attach the wire to the forward-most positive terminal on the fuse block. If you attach the wire to the fuse block, you will need to insert a 40 amp fuse in the slot closest to the terminal. If this terminal and fuse slot are already used, you can simply run the wire to the positive battery terminal via the 40 amp circuit breaker.

If there are no additional wires hanging out of the back of the 7-way connector, you will want to take the connector apart and attach the 10 gauge wire to the terminal in the 11 o clock position when looking at the back of the connector (see photo).

I have attached a general wiring diagram for hard wiring a 7-way connector and brake controller if you are attempting to install a brake controller. If the connections have not already been made, there will be two additional connections at the under hood fuse block that you will need to make to power the brake controller and brake output circuit.

You will see a blue and red wire next to the fuse block on the cab side. The blue wire has a plug on it and the red wire has a ring terminal. The red wire will connect to the closest positive post and a green 30 amp fuse is needed in the location nearest the positive post to power the brake controller. This will provide power to the brake controller.

The blue wire will need to be cut from the connector, connected to a length of 10 gauge wire and ran to the 7-way connector at the rear of the vehicle. This wire will connect to the terminal in the 7 o clock position.

If you need to make the connections for the brake output circuit and the 12 volt power lead, I would recommend purchasing the Brake Controller Wiring Kit, # 5506. This kit comes with 25 ft of duplex wire, butt connectors and ring terminals to make all of the necessary connections. The only additional parts that you would need would be the 30 and 40 amp fuses, found at any local automotive store, or a 40 amp circuit breaker.

I have attached an FAQ article that further details the installation for you to check out.