GMC C series 2002 Owner's Manual page 62

The exhaust brake indicator light is on when the exhaust
brake is in use.
When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be most
effective if the gear range selected is the lowest possible
range that does not allow the engine rpm to go more
than 200 rpm above rated (full load) rpm as shown
on the Engine Information Plate.
(Do not exceed 2,900 rpm.)
The accelerator and clutch pedals must be released in
order for the exhaust brake to engage.
The switch is located on
the upper right side of
the instrument panel and
turns the exhaust brake
on and off.
Do not use the exhaust brake when running the engine
-
at idle during warm up or other extended periods.
Prolonged use of the exhaust brake during idling will
cause the engine to overheat.
CAUTION:
Be careful when using the exhaust brake or you
could lock the wheels and lose control of the
vehicle. Operators not familiar with an exhaust
brake should not use this brake on slippery
surfaces before learning to use it on dry surfaces.
If the vehicle's wheels begin to lock when using
the exhaust brake on slippery surfaces, switch the
exhaust brake off immediately. The exhaust
brake will turn off if the anti
is activated.
-
lock brake system
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