I know that the 05's had some electrical issues. But have you tried the old standby of resetting? Disconnect the neg. on the battery for about 10-15 minutes and see if it resets and works again. I don't think it has anything to do with the lock, these keys don't have chips in them.
chevy runs deep, Don't step in chevy!
289 - Holley 4150 570cfm; Performer intake; mild cam; MSD HEI; 302 heads; Roller Tips; Hedman Tri-Y headers; H-pipe w/Flowmaster 40's; 9 in posi 3.50; 205/50-17F; 225/50-17R.