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Home >> Saturn >> 2003 >> L200 Automatic >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel, Gages, And Console >> Description and Operation >> Indicator/Warning Message Description and Operation >> Instrument Cluster Illumination

Instrument Cluster Illumination

The instrument cluster has 2 front flood illumination lamps and 4 rear back-lighting lamps. The signal to control these instrument cluster illumination lamps is a pulse width modulated voltage driven by the body control module (BCM).

The BCM varies the duty cycle based on the position of instrument panel dimmer knob. The duty cycle varies from approximately 20 percent LO to 100 percent HI. The BCM also sends class 2 messages to the cluster, to control odometer backlighting brightness, based on the position of the instrument panel dimmer knob.

Instrument Panel I/P Cluster Telltales

Telltale Gage or Lamp Input To BCM Input To Cluster
Direct Wire Serial Data Direct Wire Serial Data
ABS EBTCM - - BCM
Low Traction EBTCM - - BCM
Air Bag - - - SDM
Brake X - - BCM
Hot Coolant - ECM V6
PCM 4 CYL
- BCM
DRL X - - BCM
Charging System - ECM - BCM
High Beam Lamp X - - BCM
Left Turn Lamp - - X -
Low Brake Fluid X - - BCM
Low Coolant X - - BCM
Low Fuel - ECM V6
PCM 4 CYL
- BCM V6
PCM 4 CYL
Washer Fluid Low X - - BCM
Service Engine Soon - ECM - BCM V6
PCM 4 CYL
Change Oil Soon - ECM V6
PCM 4 CYL
- BCM
Oil Pressure - ECM - BCM V6
PCM 4 CYL
Reduced Power (V6 Only) - ECM - BCM
Right Turn Lamp - - X -
Seat Belt - - - SDM
Security X - BCM -
Service Wrench - ECM V6
PCM 4 CYL
- BCM
Decklid/Lift Gate Ajar X - - BCM
Upshift - - - PCM
Speedometer - ECM V6
PCM 4 CYL
- BCM
Odometer - ECM V6
PCM 4 CYL
- BCM
Tachometer - ECM V6
PCM 4 CYL
- BCM
Fuel Gage - ECM V6
PCM 4 CYL
- BCM
Coolant Gage - ECM V6
PCM 4 CYL
- BCM
Illumination Lamps Direct wire from BCM