Park/Marker Lamps

Voltage is applied to the Headlamp Switch at all times. With the Headlamp Switch is in "PARK" or "HEAD," voltage is applied to the Park and Marker Lamps. The Front Marker Lamps are grounded through the turn filament of the respective Front Park/Turn Lamp. The Front Marker Lamps will light as a result.

Oldsmobile and Pontiac are also equipped with automatic lamp control to turn on the Park and Headlamps when the Instrument Cluster, with the use of a Photoresistor, determines that the exterior lamps should be turned on based on available lamp level. When the Instrument Cluster grounds the Park Lamp Relay, voltage is supplied directly to the Park Lamps, bypassing the Turn/Hazard Headlamp Switch. When this occurs, the Automatic Lamp Control Relay is grounded as well, which supplies voltage from the HDLP Circuit Breaker to term "A" of Conn C1 of the Turn/Hazard Headlamp Switch Assembly which feeds the Headlamps without requiring that the Turn/Hazard Headlamp Switch be turned on. Once the available lamp reaches a predetermined level, or if the Ignition Switch is turned to "OFF," the Instrument Cluster will no longer supply ground to the Park Lamp Relay or the Automatic Lamp Control Relay, causing the lamp to be turned off.