This works for the 1993 Grand Cherokee:
Sit inside the vehicle with all the doors closed.
Place ignition in the OFF position.
Open the driver's door. Leave Open.
Move the mechanical door lever to the LOCK position.
Turn the ignition to the RUN position.
Aim the transmitter at the Keyless Entry receiver and press Lock button.
Hold for five seconds until the door locks cycle.
Turn ignition OFF within 20 seconds.