I've just purchased a 2003 Tahoe LT. Apparently my radio is different than everybody else's because none of the 2&3 or 5&right seek codes are working.

I don't want to take it to the dealership just yet. Can anyone give me some pointers? Thanks

 

I'm pretty sure once it's locked, if you don't know the PIN, the only way to unlock it is at a dealer. The whole point is to discourage theft. That wouldn't be much of a deterrent if it could be easily overridden.

ETA: From your owner's manual:

LOCKED: This message is displayed when the THEFTLOCK system has locked up. You must return to the dealership for service.

 

From the looks of the buttons you mentioned and the seek button, some previous owner has really hammered those buttons. I would contact GM customer service, give them your purchase date and VIN #. They may want to verify before giving you the RADIO CODE. The dealer doesn't have it on file (unless you know where it was sold new) so any non selling dealer has to call as well . JMHO and good luck.

PS, I would then RE-SET the code. Directions should be in OWNER MANUAL, or GOOGLE.

 

Regarding the radio buttons being 'hammered', not really. It's a common issue and replacement buttons can easily be found on eBay. I'm carefull with mine and had to have a few replaced under warranty and after a few years, they started looking funky again. Just look at the used car ad photos...