Theft-Deterrent Systems - GMC 2003 GMT560 T-Series Owner's Manual

Passenger Side Door Glass
If your vehicle has this feature, the passenger's side
door window will open to allow the inner glass to
be cleaned.
To open this window, pull out on the latch at the rear of
the window and swing the window open. When
closing the window, push firmly at the latch to close
completely.
2-6
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CAUTION:
Never open the passenger side door glass with
the ignition on. You can be injured if the
window linkage moves. Open this glass only
with the ignition off.

Theft-Deterrent Systems

Vehicle theft is big business, especially in some cities,
and even commercial vehicles are no exception.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make it
impossible to steal. However, there are ways you
can help.