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Home >> Saturn >> 2002 >> L100 L4-2.2L VIN F >> Repair and Diagnosis >> Relays and Modules >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Body Control Module >> Description and Operation >> Body Control Module Functions >> Automatic Lighting Control (ALC)
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Automatic Lighting Control (ALC)

The Body Control Module (BCM) monitors circuit 79 to determine if the headlamps (park lamp) switch is active or inactive. The Automatic Lighting Control (ALC) system will be inactive if the headlamp, parklamp switch is active. The headlamp relay is commanded on by the BCM through circuit 352. The BCM also monitors 352 for feedback when the headlamp relay is commanded. The system uses light sensor circuit 1137 to switch the ALC on after dark.