GMC 2010 T-Series Owner's Manual page 102

Hydraulic Brake System Warning Lights
Vehicles with hydraulic brake systems have two brake
system warning lights on the instrument panel.
When it comes on, you will also hear a warning tone.
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.
If the light comes on while driving, pull off the road and
stop carefully. The pedal might be harder to push or
might go the floor. It can take longer to stop. If the
light remains on, have the vehicle towed for service.
See Towing Your Vehicle on page 4 20 for more
information.
The brake system warning light may come on, and the
warning tone may sound, when you are turning and
braking at the same time. This is normal. See Hydraulic
Brake Systems under Braking on page 4 4.
3-26
If this light comes on, the
fluid level in the master
cylinder reservoir is low or
there is a problem with
the hydraulic brakes.
When this light comes on, you will also hear a warning
tone. Have the system repaired immediately.
Both of these lights should come on briefly every time
you start your engine. If they do not come on then, have
them fixed so they will be ready to warn you if there is a
problem. If one or both of these warning lights stay on
after you start the engine, there could be a brake
problem. Have your brake system inspected right away.
If one or both of these lights come 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
brake system warning light is still on, have the vehicle
towed for service. See Towing Your Vehicle on
page 4 20. See Hydraulic Brake Systems under
Braking on page 4 4 for further information.
If this light comes on, it
means there may be a
problem with the brake
system.