Cadillac 2001 DeVille Owner's Manual page 102

Reach under the driver's side of the instrument panel
and pull on the manual release lever, which is located
above the parking brake pedal. If the parking brake does
not release, your vehicle needs service.
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NOTICE:
Driving with the parking brake on can cause
your rear brakes to overheat. You may have to
replace them and you could also damage other
parts of your vehicle.
If you are towing a trailer and are parking on a hill, see
"Towing a Trailer" in the Index. This section shows
what to do first to keep the trailer from moving. For
more information, see "Brake System Warning and Park
Brake Indicator Light" in the Index.