Dodge 2009 Ram Diesel Owner's Manual Supplement page 26

24 UNDERSTANDING YOUR INSTRUMENT PANEL
INSTRUMENT CLUSTER DESCRIPTION
1. Check Gages Warning Light
This light will illuminate when the voltmeter,
engine oil pressure, or engine coolant temperature
gauge indicates a reading either too high or too low.
Examine the gauges carefully, and follow the instructions
contained below for each indicated problem.
NOTE: When the ignition switch is turned to OFF, the
fuel gauge, voltmeter, oil pressure and engine coolant
temperature gauges may not show accurate readings.
When the engine is not running, turn the ignition switch
to ON to obtain accurate readings.
2. Voltmeter
When the engine is running, the gauge indicates
the electrical system voltage. The pointer should
stay within the normal range if the battery is charged. If
the pointer moves to either the extreme left or right, and
remains there during normal driving, the electrical sys-
tem should be serviced.
NOTE:
• If the gauge pointer moves to either extreme of the
gauge, the "Check Gages Warning Light" will illumi-
nate and a single chime will sound.
• The voltmeter may show a gauge fluctuation at vari-
ous engine temperatures. This cycling operation is
caused by the post-heat cycle of the intake manifold
heater system. The number of cycles and the length of
the cycling operation is controlled by the engine
control module. Post-heat operation can run for sev-
eral minutes, and then the electrical system and volt-
meter needle will stabilize.
• The cycling action will cause temporary dimming of
the headlights, interior lights, and also a noticeable
reduction in blower motor speed.