Pontiac 2002 Grand Prix Owner's Manual page 73

To replace the battery do the following:
1. Insert a flat object like a coin into the slot on the side
of the transmitter and twist to separate the halves.
2. Gently pry the battery out of the transmitter. Do not
use the metal flanges to "pop out " the battery.
3. Put the new battery into the transmitter as shown on
the transmitter. Use a type CR2032 battery, or
equivalent type.
4. Reassemble the transmitter. Make sure the halves are
snapped together tightly so water will not get in.
5. Check the transmitter operation.
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