Hummer 2007 H3 Owner's Manual page 91

Battery Replacement
Under normal use, the battery in the remote keyless
entry transmitter should last about two years.
You can tell the battery is weak if the transmitter
will not work at the normal range in any location.
If you have to get close to your vehicle before
the transmitter works, it is 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.
To replace the battery, do the following:
1. Insert a coin, or similar object, in the slot
between the covers of the transmitter
housing. Gently pry the transmitter apart.
2. Remove and replace the battery with a
three-volt CR2032 or equivalent battery.
3. Align the covers and snap them together.
4. Check the operation of the transmitter.
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