GMC Chevrolet SSR 2003 Owner's Manual page 143

Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power
at engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.
You can only drive for a short time with the reading
in either warning zone. If you must drive while the gage
is in the warning zone, turn off all unnecessary
accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Instantaneous Fuel Consumption Gage
The instantaneous fuel consumption gage shows the
rate of fuel that is being used in gallons per hour (gph).
This gage (B) is located in
the center of the gage
package.
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