When the headlamp switch is in the PARK or the HEAD position, battery voltage is supplied to the following components:

When the lamp dimmer module is turned off, no voltage is supplied to the interior lamps.

When the dimmer switch is turned to the LO position, the dimmer switch supplies a minimum voltage to the lamp dimmer module. The lamp dimmer module then supplies a low voltage to the interior lamps. As the dimmer switch is turned to the HI position, the voltage signal to the lamp dimmer module increases. This condition causes the lamp dimmer module to supply a proportionately increasing voltage to the interior lamps.