need to know how to connect auxillary power to my truck to charge breakaway battery. auxillary power connection on 2008 chevy 2500 duramax
asked by: Jared V
If the 12 volt power pin (#4 pin at 1:00 position) on the 7-way connector on your 2008 Chevrolet Silverado 2500 is being used for a trailer battery you can use the center pin on the 7-way as an auxiliary power source. You can wire the center pole of your 7-way as an auxiliary power connection by running a 10 gauge wire, part # 10-1-1, to the positive post of the vehicles battery through a 40 amp circuit breaker, part # PK54540. If you wire your auxiliary power this way you will want to make sure the center pin on your trailers 7-way connector is also wired for the 12 volt power and the breakaway battery is connected to that center pin.
If the 12 volt power pin is not being used you will want to check and make sure you have 12 volt power to your 7-way connector at the rear of your 2008 Chevrolet Silverado 2500. You can use a circuit tester like the Quickee Tester, part # 3808, and test the number 4 pin on your 7-way, which is located at the 1:00 position, if you are looking at the front of the 7-way. See picture of 7-way to the right. This is the 12 volt power wire and when the 7-way connector from your trailer is plugged in it will provide the power needed to maintain a charge on your breakaway battery.
If you do not have power at the 7-way on your vehicle you will want to check a couple of connections under the hood to complete the trailer wiring package on your vehicle. The ring terminal for the 12-volt power lead for the 7-way trailer connector is located to the left of the power distribution box, and is taped to a wire harness under the power brake booster. You are looking for a red wire with a ring terminal on the end. This wire needs to be connected to the right side stud at the front of the power distribution box. You will also want to make sure there is a 40 amp fuse installed adjacent to the stud.
While you are under the hood you should probably go ahead and connect the brake controller power wire to the left side stud also. This wire is located at the right side of the power distribution box next to the fender and will also have a ring terminal on the end. This connection will also need a 30 amp fuse installed adjacent to the stud.
I am including a link to a FAQ page that will show where the wires are located and how to connect the wires. The information is at the end of the page where it says finalizing connections. Also, see the picture to the right that will show where the wires are under the hood.