Cadillac 2004 DeVille - Manual (Page 288)

The fuel door release
button is located to the
left of the steering wheel
next to the exterior
lamp control.
The button only works when the vehicle is in PARK (P)
or NEUTRAL (N), when the key is in the ignition and
the VALET lockout button is in OFF.
An alternate fuel door
release is located inside of
the trunk on the driver’s
side. Pull it to release
the fuel door.
While refueling, hang the fuel cap by the tether from
the hook on the filler door.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). The fuel cap has spring in it; if you
let go of the cap too soon, it will spring back to the
right.
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