Circuit Operation

The Headlamp system with daytime running lamps is controlled by the Instrument Cluster. The system operates by allowing the headlamps to operate at a reduced intensity when the vehicle is operating (the engine is running and transaxle is not "PARK") and the normal headlamps are not on. The Instrument Cluster turns the system on by grounding the 592 CKT, thereby energizing the Daytime Running Lamps Relay. This will allow a reduced voltage (6 volts) to flow across the headlamps. If the car has a fog lamp option, the Daytime Running Lamps and Fog Lamp Relay will also be energized (with the "PARK" lamps on) allowing normal fog lamp operation. When the Headlamp Switch is turned "ON," the Instrument Cluster allows normal Headlamp operation.

The Instrument Cluster also has an input from the Park Brake. If the Park Brake is in the "ON" position, the Daytime Running Lamps will remain disabled until the Park Brake is put in the "OFF" position. With an automatic transaxle, the Instrument Cluster will also disable the DRL lamps until the transaxle has been taken out of "PARK."

The Instrument Cluster also Controls the Automatic Lamp Control (ALC) by grounding the ALC relay. The Instrument Cluster uses a Photoresistor to determine lamp levels, and when to ground the ALC Relay. The Instrument Cluster also grounds the Park Lamp Relay to turn on the exterior lamps. refer to Exterior Lights for further information. When the Instrument Cluster grounds the ALC Relay to turn on the headlamps, it will remove ground to the Daytime Running Lamps Relay, Turing the DRL Lamps off.