You will need to find the ECU for the
alarm/keyless RS3000 system. it is usually under the drivers seat.(or behind the dash) Looking at the side with the connectors on it, there is a small button or hole on the right-hand side.

you will need to press the button or insert a
paper clip into the hole to press the button inside, following the instructions below:
  The Status Monitor is the the Red LED light on the dash that says "security" under it. This procedure seems quite simple,
although the manual still advises one to contact a dealer to do it. Be sure that you follow the procedure exactly or
there is a chance that you might mess up the programming of the original remote. If that happens, just follow the procedure again to add the remote back to the system.

1. Insert key into the ignition switch and turn to "ON".

2. Press and hold the ECU's programming switch for 3 seconds.
The Status Monitor LED turns on for 5 seconds.

YOU MUST PERFORM THE NEXT STEP WITHIN 5 SECONDS!

3. Press and release the remote control's top or bottom button
(whichever one you want to operate the system).
The Status Monitor LED turns off.
The Piezo "chirper" chirps once.
The exterior lights flash once.

4. Turn off the ignition. The ECU will now operate with the remote
just programmed.