GMC 1997 Safari Owner's Manual page 83

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.
To replace the battery:
NOTICE:
When replacing the battery, use care not to
touch any of the circuitry. Static from your
,
the transmitter.
body transferred to these surfaces may damage
Use one Panasonic@ three volt, type CR2032, or
equivalent battery.
Your transmitter housing snaps apart for ease in
battery replacement.
1. Insert a small coin, or flathead screwdriver, to
separate the bottom of the transmitter from the top.
2. Remove the battery and replace it with a new one,
making sure the positive side
(+)
side of the battery
is facing down.
3. Snap the top and bottom together.
4. Test the operation of the transmitter with your
vehicle. If the transmitter does not work, try
synchronizing the transmitter with the receiver.