Chevrolet 2003 Silverado 1500 Pickup Owner's Manual page 166

Setting Cruise Control
If you leave your cruise control on when you're
not using cruise, you might hit a button and go
into cruise when you don't 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
4. Take your foot off the accelerator pedal.
release it.
The cruise light on the instrument panel will illuminate
when the cruise control is engaged.
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.
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