keyless entry woes

[porkchopsocr]

My keyless entry stopped working on me, and I cant figure out what it is. I've changed the battery on the remote, but nothing.Any advice would be great. Its for a 2003 Blazer.

[MT-2500]

TRY A TRANSMITTER RESYNCHRONIZATION

Resynchronization may be necessary due to the security method used by the remote keyless entry system. The transmitter does not send the same signal twice to the remote control door lock receiver (RCDLR).
The RCDLR will not respond to a signal that has been sent previously. This prevents anyone from recording and playing back the signal from the transmitter.
Resynchronization may be necessary under the following conditions:
If The battery in the transmitter is very weak.
If The battery in the transmitter was replaced.
If the car battery has been run down weak or dead
Simultaneously press and hold the LOCK and UNLOCK buttons on the transmitter for 7 seconds .

The horn should chirp in order to confirm synchronization.

[Onblsht]

The 7 second resync is necessary on most GM remotes if you change the battery on one that was completely dead.