Remote Keyless Entry- locks door, but doesn't unlock. HELP!!

[nups]

I just bought a 1995 pathy. It came with an OEM remote keyless entry (RKE) fob (looks old and worn down). When I first hooked up the control module under the seat (it was disconnected), the RKE would lock and unlock the doors fine. Additionally when I pressed the horn button, it would beep twice, the parking lights would flash, nothing would happen, and the unlock, lock function would not work until I put the key back into the ignition and turned it on.

After about a week now, the RKE will lock the doors, but will not unlock. When the doors are locked and I press the lock/unlock button on the fob, the pathy beeps and the lights flash, but it doesn't unlock. And now when I press the horn button on the fob nothing happens.

Please help!!