Pontiac 2004 Bonneville - Manual (Page 163)

This light should come on briefly when you turn the
ignition key to ON. If it does not come on then, have it
fixed so it will be ready to warn you if there is a
problem.
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 release fully. If you try to drive off with the parking
brake set, a chime will also come on until you
release the parking brake. If the light stays on after your
parking brake is fully released, it means you have a
brake problem.
If you have the optional Driver Information Center (DIC),
a PARK BRAKE SET message will be displayed
while the parking brake is set.
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.
{ 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.
United States Canada
3-43