GMC 1999 Sierra 1500 Pickup Owner's Manual page 286

Service & Appearance Care
This light also should come on when you start your engine, as a check. If it
doesn't, have it fixed so it will be there to let you know if you ever do get
water in your fuel.
If the light comes on at any other time, use this chart.
"WATER IN FUE
PROBLEM
Light comes on intermittently.
1) Temperatures above freezing.
Light stays on
2) Temperatures below freezing.
3) Immediately after refueling
-
Large amounts of water
probably pumped into the
tank.
."
LIGHT CHART
RECOMMENDED ACTION
Drain water from fuel filter.
Drain fuel filter immediately. If nc
water is drained and light stays on
-
replace fuel filter.
Drain fuel filter immediately. If no
water can be drained
-
water may be
frozen. Open air bleed to check for
fuel pressure. If no fuel pressure
replace filter.
Fuel tank purging required. See your
dealer for assistance.
1
iesitation or "flat" performance at high speed or hard acceleration may be an
ndication of premature fuel filter plugging due to dirty or contaminated fuel.
The filter element may need
to
be changed if this happens. See your dealer
or assistance.
f you drive when this warning light is on, you can damage your fuel
I
njection system and your engine. If the light comes on right after you
efuel,
it
means water was pumped
into your fuel tank. Turn off your
mgine immediately. Then, have the water drained at once.
I
To
drain water:
1.
Remove the fuel tank cap.
2.
Connect a hose going from the water drain valve to a fuel-resistant
container.
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