I put in a new audio system and now the truck won't stay running.
I installed a new audio system in my 2003 GMC Sierra and now it will crank and start, but shuts off as soon as I release the key. I used the yellow ignition wire from the ignition switch to power the system. I have the same issue after I removed the power from the audio system.
I think I got it fixed. Apparently, you sometimes have to wait 5 minutes to try restarting after battery disconnection.