GMC 1998 Savana Van Owner's Manual page 80

Operation
To unlock the driver's door, press the UNLOCK button.
If you press this button again within five seconds, all the
doors will unlock. Press the REAR 2X button twice to
unlock the rear door only. When the UNLOCK or
REAR 2X button is pressed, the interior dome lamps are
turned on for 40 seconds or until the ignition switch is
activated. Press LOCK to lock all doors.
Matching Transmitter(s) To Your Vehicle
Each remote keyless entry transmitter is coded to
prevent another transmitter from unlocking your vehicle.
If a transmitter is lost or stolen,
a
replacement can be
purchased through your dealer. Remember to bring any
remaining transmitters with you when you go to your
dealer. When the dealer matches the replacement
transmitter to your vehicle, any remaining transmitters
must also be matched. Once your dealer has coded the
new transmitter, the lost transmitter will not unlock your
vehicle. Each vehicle can have only two transmitters
matched to
it.
Battery Replacement
Under normal use, the battery in your remote keyless
entry transmitter should last about two years.
You can tell the battery is weak if the transmitter won't
work at the normal range in any location. If you have to
get close to your vehicle before the transmitter works,
it's probably time to change the battery.
NOTICE:
When replacing the battery, use care not to touch
any of the circuitry. Static from your body
transferred to these surfaces may damage the
transmitter.
Use one Pmasonic@ type CR2032 battery:
2-8