GM Service Manual Online
For 1990-2009 cars only

When the headlamp switch is in the PARK or the HEAD position, battery voltage is applied to the following components through the INST LPS fuse through CKT 32:

    • The panel dimmer switch
    • The lamp dimmer module

When the lamp dimmer module is turned OFF, no voltage is applied to the interior lamps.

When the dimmer wheel is turned to the low position, the dimmer switch applies a minimum voltage to the lamp dimmer module through CKT 44. The lamp dimmer module then applies a low voltage to the interior lamps through CKT 8. As the dimmer wheel is turned to the high position, the voltage signal to the lamp dimmer module increases. This condition causes the lamp dimmer module to apply a proportionately increasing voltage to the interior lamps. Ground for the lamps is supplied by the individual components in which the lamps are located.