Need to find a live wire under dash of Chev class C

Have you looked under the dash near the pedals? My 2010 21QB comes with a few stub outs that are IGN 12V, ready to be wired. Mine is on a Ford chassis, so I'm not sure if it's just a Ford thing. Having a test light will make this task simpler.

I found a stubbed out wire in front of the firewall which was triggered by reverse, I tied into that wire when I installed a backup camera and also tied into the camera lead with 12v power with a switch, in line, installed on dash. I utilized 1/4 amp diodes to keep from back powering the opposite lead that way the camera could be turned on when put in reverse, or I could switch it on to check the toad or traffic while going down the road. My Rig is a 2003 Fleetwood Storm, on a Workhorse P-30 chassis.

I hooked mine up to the house 12 V supply to avoid this difficulty. The current draw was way less than an ampere, so I hooked to the same fuse as the propane detector. I ran a pair of wires through cupboard bottoms to a switch I put on the driver's seat. Handy to be able to use that camera without turning on the ignition occasionally. Not so handy when driving with the house battery cutoff on - I may change to connecting the camera to the battery itself, through a 1 amp fuse of course.

99% of the backup cameras I install on work trucks (everything from 3/4 ton vans to class 8 big rigs) are systems which only require a few amps to operate. Tapping into an extra ignition switched circuit in the fuse block is great when it's easily accessible, but if that it not convenient, then piggy-backing the camera off the cigarette lighter or the radio can work fine - just make sure you use the inline fuse provided with the camera system.

My 2004-based Chevy only ran the radio in the IGN position. I don't know if they have changed the factory wiring, but there was a four wire harness from the chassis, behind my radio. (The MH maker installed the radio.) The four colors were brown, red/white, black, and white. They hooked up the main radio power to the brown, which was an IGN circuit. The red/white is hot all the time. I don't recall the functioning of the black and white, but they didn't come into play for what I was working on.

I hooked my camera to the fuse panel as dbbls mentioned. It works nice.
Mine is hooded to an on off toggle switch.

I suggest you go to the fuse panel and find one. There are usually open slots and you could put the correct fuse in. Get a tester and find one that is hot all the time.

This may be of help, it tells the colors and the location of the wires.

Wiring

Hope this useful.

Check out GM UPFITTER site. Look under Body Builder Manuals. Then light duty. Then prior to 2011.