Pontiac 2003 Montana Owner's Manual page 115

Battery Replacement
Under normal use, the battery in your remote keyless
entry transmitter should last about three 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.
1. Insert a flat object like a coin into the slot on the
side of the transmitter and twist it to separate
the halves.
2. Gently pry the battery out of the transmitter. Do not
3. Replace the battery.
4. Reassemble the transmitter. Make sure the halves
are snapped together tightly so water will not get in.
5. Press and hold the LOCK and UNLOCK buttons for
seven seconds to synchronize the transmitter.
6. Check the transmitter operation.
use the metal flanges to pop out the battery.
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