Voltmeter Gage; Up-Shift Light (Manual Transmission) - GMC Sierra Classic 2007 Owner's Manual

Voltmeter Gage

While the engine is running, this gage shows the
condition of the charging system. The gage
may transition from a higher to lower or a lower to
higher reading. This is normal. Readings
between the low and high warning zones indicate
the normal operating range. The voltmeter
gage may also read lower when in fuel economy
mode. This is normal.
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
When the engine is not
running, but the ignition
is in RUN, this gage
shows your battery's
state of charge in
DC volts.
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,
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.
Up-Shift Light
(Manual Transmission)
It will come on when you should shift to the next
highest gear. It will help the vehicle get the
best fuel economy.
Your vehicle may have
an up-shift light.
251