I just got my 03 Tahoe 3 days ago and installing my Sony head unit has been hell. I got a scosche gm2000 wiring harness and it has a 12v red wire that plugs to the stereo wiring. Now when I turn the key the stereo works, but when I start my truck it stays on for about 5 seconds then shuts off. I googled it and everyone says you have to run a separate wire from somewhere to the 12v wire. My first try fried the wiring harness. Haha. I've got a new harness. Same problem. Can someone tell me where to run it?