Chevrolet 2002 Silverado 1500 Pickup Owner's Manual page 246

The following steps must be performed on each of the
-
push pins to remove the air dam:
4-18
1. Insert a tool into the
-
push pin slot and pull
downward until the
-
push pin snaps loose.
2. While continuing to pull
downward on the
-
push pin, squeeze and
turn the expandable end
-
of the push pin with a
tool until it releases
from the retainer.
When you're back on roads, though, be sure to replace
the air dam.
NOTICE:
Operating your vehicle for extended periods
without the front bumper lower air dam installed
can cause improper air flow to the engine and
may allow things like fog lamps or tow hooks on
the front of your vehicle to be damaged. Always
be sure to replace the front bumper air dam
when you're finished off
-
3. Pull the push pins and
lower air dam assembly
away from the retainers
until the lower air dam
is free.
-
road driving.