I recently replaced my radio with identical one from junkyard, and it says "locked" on screen. I've heard serial numbers had to match, but there was a way to bypass. Any suggestions?
It's the 'Theftlock' feature, happens too if you disconnect the battery. You need to reenter the radio's code. See: How to Unlock Your Locked GM Theftlock Radio - http://www.wikihow.com/Unlock-Your-Locked-GM-Theftlock-Radio
Search GMC Sierra 1500 Questions
GMC Sierra 1500 Experts