The Daytime Running Lamps (DRL) control module is designed to automatically operate exterior lights depending on outside light conditions. The DRL control module operates in two modes, the day mode and the night mode. In the day mode, the DRL ambient light sensor senses daylight. Then, the DRL control module turns on the front turn lamps (non-flashing) if under the following conditions:

In the night mode, the DRL ambient light sensor senses darkness. Then, the DRL module turns off the front turn lamps and turns on the headlamps through circuit 10. The DRL module also turns on the park, side marker, license, and tail lamps. If the engine should stall with the DRL control module in the night mode, the DRL control module will turn off the headlamps and leave the side marker, park, license and tail lamps on while the engine is being cranked. The headlamp switch operates as usual.

The DRL control module receives voltage from the DRL fuse through circuit 1239 and the HVAC fuse through circuit 41. The park lamps and/or the headlamps may be operated manually at any time by using the headlamp and instrument panel lamp dimmer switch. The DRL module will not operate if the system voltage is less then 9 volts or greater then 18 volts.

The DRL ambient light sensor is a light sensitive variable resistor. Its resistance decreases as outside light intensity increases. The DRL control module measures the voltage drop across the DRL ambient light sensor and determines whether it should operate in the day mode or night mode.

If the park brake is applied before the ignition switch is turned on, the DRL control module will not operate any headlamps or exterior lamps. This allows the operator to start the engine and keep the headlamps off, as long as the park brake is applied. When the park brake is released with the ignition switch on, the DRL control module will activate the headlamps.

This feature will only function when the park brake is applied before the ignition switch is turned on. If the park brake is applied after the ignition switch is turned on, the headlamps will not turn off.

Voltage is applied from the FRT PARK LPS fuse when the park lamps are on, through circuit 9 to the underhood accessory wiring junction block, then to both front side marker lamps and front park lamps.

Voltage is applied at all times from the LP PARK fuse to the headlamp switch and to the Daytime Running Lamps (DRL) control module through circuit 1340. With the headlamp switch in the PARK or HEAD position, voltage is applied to circuit 74. Current flows through circuit 74 to the TAIL LAMP fuse through circuit 301, to all rear side marker, tail and license lamps turning them on.

With the ignition switch in the on or start position, voltage is applied from the TURN SIGNAL CRN LPS fuse to the normally closed pole of the hazard warning switch through circuit 539, which feeds the turn signal switch through circuit 16. Current flow heats the timing element in the hazard warning switch and continuously opens and closes the circuit. When the turn signal switch is in the turn left position, voltage is applied to the turn signal switch circuit 1414 at terminal C of connector C201. Voltage flows through circuit 1414 to the instrument cluster for the left turn telltale lamp, LR turn signal lamp and the DRL control module. The DRL control module applies the voltage through circuit 14 to the underhood accessory wiring junction block to the LF turn signal lamp. The RH turn signal works the same way through circuit 1415 and circuit 15.

Voltage is applied at all times from HAZARD fuse to the normally open poles of the hazard warning switch through circuit 1840. With the hazard warning switch in HAZARD, current flow heats the timing element in the hazard warning switch, and it continuously opens and closes circuit 1414 and circuit 1415 to all the turn lamps and both turn telltale lamps. All of the turn lamps and both turn telltale lamps flash on and off.

Voltage is applied at all times from the STOP LAMPS fuse to the stop lamp switch through circuit 140. When the brake pedal is depressed, voltage is applied from the stop lamp switch through circuit 17 turning on the LH and RH stop lamps and to the Center High Mounted Stop Lamp (CHMSL), turning on the CHMSL.

Voltage is applied when the ignition switch is in the on position through the TURN SIGNALS CORN LPS fuse in the fuse block, to the turn signal switch through circuit 539. When the turn signal switch is placed in the TURN LEFT position, voltage is applied through the closed contacts of the turn signal switch, to the LH cornering lamps through circuit 57.

The LH cornering lamps are grounded through circuit 1350 to G101. When the turn signal switch is placed in the TURN RIGHT position, voltage is applied through the closed contacts of the turn signal switch, to the RH cornering lamps through circuit 58. The RH cornering lamps are grounded through circuit 1250 to G102.