[trackbird]

Your wiring may be similar to mine (2008 Silverado.) You will see modular plugs just above and to the left of the spare tire. Trace the wires running to a rear tail light. I chose the driver's side.
The correct wire to splice into was the green wire. The yellow wire goes to the turn signals, and the brown one is for the brakes. I grounded the black wire to the frame rather than splicing another wire.
I just put it in today, and still haven't found the correct hot wire from the fuse box. I plan to use the accessory lighter adapter until I figure it out. Maybe someone else can chime in with that info.

 

[trackbird]

I know what you meant, red. I could have used that source for the power to the camera. I'm looking for a hot source inside the cabin. I don't want to have to run another wire thru the firewall yet.

My truck is red, also. I had no idea that red was harder to keep clean than black...but now I know.