Chevrolet 1999 Silverado 1500 Pickup Owner's Manual page 206

To replace the lower air dam:
4-16
1. Line up each push-pin
with it's intended
retainer and push the
washer portion of the
push-pin towards the
retainer until it locks
into place.
2. Push the flat end of the
push-pin towards the
retainer until it locks
into place, making sure
each is secure.
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