Cadillac 2004 DeVille - Manual (Page 175)

When the ignition is on, the brake system warning light
will also come on when you set your parking brake.
The light will stay on if your parking brake does not fully
release. If it stays on after your parking brake is fully
released, it means you have a brake problem.
{ CAUTION:
Your brake system may not be working
properly if the brake system warning light is
on. Driving with the brake system warning light
on can lead to an accident. If the light is still
on after you have pulled off the road and
stopped carefully, have the vehicle towed for
service.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the
floor. It may take longer to stop. If the light is still on,
have the vehicle towed for service. See Towing
Your Vehicle on page 4-31.
Anti-Lock Brake System Warning
Light
With the anti-lock brake
system, the light(s) will
come on when your engine
is started and may stay
on for several seconds.
That is normal.
If the light stays on, turn the ignition to OFF. Or, if the light
comes on when you are driving, stop as soon as possible
and turn the ignition off. Then start the engine again to
reset the system. If the light still stays on, or comes on
again while you are driving, your vehicle needs service. If
the regular brake system warning light is not on, you still
have brakes, but you do not have anti-lock brakes. If the
regular brake system warning light is also on, you do not
have anti-lock brakes and there is a problem with your
regular brakes. See Brake System Warning and Parking
Brake Indicator Light on page 3-48.
The anti-lock brake system warning light should come
on briefly when you turn the ignition key to ON. If
the light does not come on then, have it fixed so it will
be ready to warn you if there is a problem.
3-49