Chevrolet 2003 Silverado Owner's Manual page 168

Setting Cruise Control
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CAUTION:
If you leave your cruise control on when you
are not using cruise, you might hit a button
and go into cruise when you do not want to.
You could be startled and even lose control.
Keep the cruise control switch off until you
want to use cruise control.
1. Move the cruise control switch to on.
2. Get up to the speed you want.
3. Press in the set button at the end of the lever and
release it.
4. Take your foot off the accelerator pedal.
3-12
Resuming a Set Speed
Suppose you set your cruise control at a desired speed
and then you apply the brake or press the clutch
pedal (if equipped). This, of course, disengages the
cruise control. But you don't need to reset it.
Once you're going about 25 mph (40 km/h) or more,
you can move the cruise control switch from on to
resume/accelerate briefly.
You'll go right back up to your chosen speed and stay
there.
If you hold the switch at resume/accelerate briefly, the
vehicle will keep going faster until you release the switch
or apply the brake. So unless you want to go faster,
don't hold the switch at resume/accelerate.
The cruise light on the
instrument panel will
illuminate when the cruise
control is engaged.