Under Hood Switched Circuit

gvbhunt · March 10, 2010

Ok, I KNOW that this has probably asked but my search-fu has not uncovered anything. I have a 2007 GMC Sierra (in the sig) and I am trying to find a circuit in the UBEC that is ignition switched but either I am blind, dumb, or there is not one (heck, could be all 3 ). I am trying to wire up my new Firestone Ride-Rite wireless air command unit and it has a positive, neg, and a ignition switched wire lead for its controller. I would prefer to not have to run wires up into the cab. So if anyone knows of one, I would greatly appreciate knowing where it is.

mfennema · March 10, 2010

Pretty sure the only switched lead is in a junction box behind the brake pedal inside the cab. There is a grommet to enter the cab close to it however to make it easy access for you.

2009 Sierra · March 10, 2010

Under the hood on my 2009 I used Fuse #52, "HVAC IGN". Not sure if the 07's are the same.

gvbhunt · March 10, 2010

Excellent. I will look for that fuse before I start making holes. I hate making holes...

2009 Sierra · March 10, 2010

On a side note, if anyone knows of a fuse under the hood that is Keyed, but hot until the driver's door opens (ala the Stereo) I'd be VERY interested.

mfennema · March 10, 2010

Sorry, I was thinking of something with RAP power like you are wanting and I pointed out on the inside of the cab. I don't know of any outside RAP sources.

brims · March 10, 2010

The SEO/ALC circuit is an unused (if you don't have the roof lighting for plowing) 10A circuit hooked to the run/crank relay. The '08 manual shows a pink wire, it comes out of the fuse block X5 connector, pin G5.

For the location, if you remove the underhood fuse block and you're at the driver's fender, the X5 connector is in the row closest to the fender second connector from the front of the truck. I think those connectors some of the pins are labeled like first and last in a row.

I don't know of any RAP power under the hood.