Cadillac 1998 Seville Owner's Manual page 70

Battery Replacement
Under normal use, the battery in your remote keyless
entry transmitter should last about four 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.
I
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 coin into the notch near the key ring of the
transmitter. Turn the coin to separate the two halves
of the transmitter.
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