Operation CHARM: Car repair manuals for everyone.

General Information

Battery voltage is applied at all times to the Headlamp Switch. When the Headlamp Switch is in "HEAD" or "PARK" voltage is applied through I/P Fuse #42 to the I/P Dimmer Switch.

The I/P Dimmer Switch controls the brightness of the Panel Lamps by means of a rheostat. When the Dimmer Switch is turned to the "MAX" position, the resistance is reduced to 60 ohms and the Panel Lamps are bright. When the knob is turned to "LO," the resistance increases to about 190 ohms and the Panel Lamps dim. Chevrolet models use an additional module to control Instrument Panel Lamp brilliance.