When the headlamp switch is in the PARK or HEAD positions, battery voltage is applied to the following modules:

When the lamp dimmer module is turned off, no voltage is applied to the interior lamps. This also disables the headlamps-on warning.

A minimum voltage is applied to the lamp dimmer module when the dimmer switch is in the LOW position. The lamp dimmer module then applies a low voltage to the interior lamps. As the dimmer switch is moved toward the HIGH position, the voltage signal to the lamp dimmer module increases. This action causes the lamp dimmer module to apply a proportionally increasing voltage to the interior lamps.