When the park lamps are on, battery positive voltage (B+) is supplied through the instrument panel (IP) fuse block INT LPS fuse via CKT 32 (YEL) to the dimming switch. The dimming switch supplies a variably controlled voltage to the dimmer module(s). The potentiometer in the panel dimming control cannot provide enough current in order to operate the panel lamps. The dimmer module(s) amplifies the current, supplying the variable voltage to the panel lights. As the amount of the current increases, the lamps become brighter. As the amount of the current decreases, the lamps become dimmer.

Oldsmobile

There are 2 dimmer module that supply current to the panel lights. The right dimmer module supplies current via CKT 8 (GRY) to the following components:

The left dimmer module supplies current via CKT 1244 (BRN) to the following components:

Buick

There is only 1 dimmer module that supplies current to the panel lights. The left dimmer module supplies current via CKT 8 (GRY) to the following components:

The parade dimming feature prevents the dimming of the VF displays when daylight is sensed by the lamp control module (LCM) and the park lamps are turned on manually. If the LCM senses night time conditions and the park lamps are on, the LCM allows the VF displays to be dimmed.

All of the modules with the VF displays receive the dimming level from an input on CKT 8 (GRY) or CKT 1244 (BRN). When the LCM determines that the above conditions are met, the LCM sends a signal to the instrument cluster and the radio via CKT 390 (YEL). For Buick, the radio then relays this information to the heater and A/C programmer and passenger temperature control via CKT 724 (PPL/WHT). The modules with the VF displays then adjust the dimming level of their VF displays to match the level of the incandescent lights.