I just bought a 2000 Silverado Z71, and supposedly when you hit the lock button on the remote twice within 3 seconds, the horn will chirp. Mine does not do this. The only thing I can get my remotes to do is lock the doors and unlock the doors. Also, I thought when you hit unlock once, it would unlock the driver's side, then when you hit unlock again, it would unlock the passenger's side. Mine unlocks both sides at the same time. Am I doing something wrong? Thanks for any help.