I just purchased a 2002 Sierra and it came with no key fobs and has a sticker on the window for an aftermarket alarm system. I purchased replacement OEM fobs FCCID: KOBLEAR1XT and they won't program. I use the directions to enter programming mode (insert key, hold unlock, cycle ignition twice and release) and it will make some extra noises like it's cycling the locks but they never cycle, and the remotes won't program. I tried disconnecting the battery for a while and trying again but same result. Any suggestions what to try next? I'm thinking possibly a bad RCDLR but looking for other options to try before I replace that. Thanks!