Instrument Cluster Indicator Operation - GMC Chevrolet Camaro 1998 Service Manual

8-538 Instrument Panel, Gauges and Console
At the base of the speedometer pointer pivot is a
magnet that is acted upon by the magnetic fields of
the 2 coils. The relative strength of the 2 magnetic
fields determines the position of the magnet and
accordingly, the position of the speedometer pointer.
Pulses from the solid state circuit also are used in
order to drive a small electric stepper motor. The
stepper motor turns the numbered wheels of
the odometer and the trip odometer. The numbered
wheels are geared so that when any one wheel
completes a revolution, the next wheel to the left is
turned one-tenth of a revolution. Every tenth of a
revolution advances the displayed number by one unit.
The trip odometer can be reset to zero at any time.
This allows the driver to record the distance traveled
from any selected starting point.
Tachometer
The tachometer signal comes from the PCM. The
tachometer displays the engine speed in thousands
of revolutions per minute (rpm).
Voltmeter
The voltmeter is an instrument that shows the voltage
of the vehicle electrical system. The voltmeter
indicates the ability of the charging system to keep the
storage battery charged. The voltmeter is wired in
parallel with other circuits in the vehicle.
When the engine is running the voltmeter indicates
charging system voltage. If the engine is not running
and the ignition switch is in the RUN or ST ART
position the voltmeter will show battery voltage. The
voltmeter can be used as a first step in diagnosing
many electrical problems. Battery voltage drop can be
seen while the engine is cranking. After the engine
is running, generator output voltage is indicated.
The voltmeter should read between 11-13 volts during
extended idle or just after starting. As the electrical •
load is increased, or in stop-and-go driving, the pointer
may rotate temporarily to th~ bottom of the scale. A
voltmeter reading continuously below 11 vol.ts or above
16 volts indicates an electrical system problem.
Instrument Cluster Indicator Operation
Fasten Seat Belts Indicator Lamp
The FASTEN SEATBELTS indicator lamp will go on
when one of the following conditions exist:
• The ignition switch is in the RUN position.
• The ignition switch is in the BULB TEST position.
• The ignition switch is in the ST ART position.
• The driver's seatbelt is unbuckled.
The FASTEN SEATBELTS indicator lamp will remain.
on until the driver's seatbelt is buckled.
For more information, refer to Audible Warnings
Description Warning/Reminder Chimes.
Body and Accessories
Turn Signal Indicator Lamps
The left or right turn signal indicator lamp will illuminate
when the multi-function lever on the left side of the
steering column is moved to signal a turn. The (
turn/hazard switch in the steering column receives an .
on-and-off flashing current from the fuse block and
the turn signal flasher unit in the convenience center
when the ignition switch is in one of the following
positions:
• RUN
• START
• BULB TE~,T
When the multi-function lever is moved the turn/hazard
switch routes the current to circuits that feed the
following lamps:
• The left front turn signal lamp
• The right front turn signal lamp
• The left rear tail/stop/turn signal lamps
• The right rear tail/stop/turn signal lamps
The circuit to the left or right front turn signal lamp,
and the cornering and sidemarker lamps has a branch
that feeds the appropriate turn indicator. lamp in the
instrument cluster. This causes the lamps to flash
when the exterior lamps are indicating a turn.
When the hazard warning button on the right side of
the steering column is pressed in the following
lamps ir\ the instrument cluster flash:
• The left front turn signal lamps
•. The right front turn signal lamps (
• The cornering lamps
• The sidemarker lamps
• The rear tail/stop/turn lamps
• Both turn signal indicator lamps
Power for the hazard warning system reaches the
turn/hazard switch from the fuse block and the hazard
flasher in the convenience center. Power is supplied
with the ignition switch in any position. When the
hazard warning system is flashing, the turn signal
circuits are inoperative.
Air Bag Indicator Lamp
The AIR BAG indicator lamp will light in order to warn
the driver of a potential supplemental inflatable
restraint (SIR) system problem that could prevent the
proper deployment of the air bags in an accident.
When the ignition switch is first turned on, the lamp will
flash seven times. This flashing verifies the proper
operation of the lamp circuit and the sensing and
discriminating module (SOM). A scan tool can be used
in order to read diagnostic trouble codes (DTCs) in
the SDM and to clear all DTCs after repair. For
additional information, including service precautions,
refer to Supplemental Inflatable Restraints (SIR).