The Daytime Running Lamps (DRL) module is designed to automatically operate the exterior lights, depending on the outside light conditions. The DRL control module operates in 2 modes:

The DRL module operates in the night mode when the DRL ambient light sensor senses darkness. When this happens, the night mode contacts close and voltage is applied to the headlamps and other exterior lights through the same circuit path as when the headlamp switch is in the HEAD position.

The DRL module turns off the headlamps when the engine stalls with the DRL in the night mode. The side marker, park/turn and tail lamps are on while the engine is being cranked. The headlamp switch operates as usual.

The DRL ambient light sensor is a light sensitive variable resistor. The DRL ambient light sensor decreases in resistance as outside light intensity increases. The DRL module measures the voltage drop across the DRL ambient light sensor. The DRL module then determines whether the day mode or the night mode should be in operation.

The DRL module will not operate any headlamps or exterior lamps if the park brake is applied before the ignition switch is turned to RUN. This allows the operator to start the vehicle and keep the headlamps off as long as the park brake is applied. The DRL module will activate the headlamps when the park brake is released with the ignition switch in RUN.

The park brake input feature will only function when the park brake is applied before the ignition switch is turned to RUN. The headlamps will not turn off if the park brake is applied after the ignition switch is turned to RUN.

Whenever the park lamps are on, voltage is applied from the TAIL LPS fuse through the headlamp switch through circuit 9 to both the front side marker lamps and the front park/turn lamps.

Voltage is applied at all times from the TAIL LPS fuse to the headlamp switch and the Daytime Running Lamps (DRL) module through circuit 240. Voltage is applied to circuit 9 when the headlamp switch is in the PARK or the HEAD position. Voltage then flows to all rear park/turn, rear side marker, tail and license plate lamps, turning then on.

Voltage is applied from the TURN B/U fuse to the normally closed pole of the hazard switch in the turn signal switch when the ignition is in the RUN position. The voltage then flows through circuit 141, which feeds the turn signal lamp flasher. With the turn signal switch in the turn left position, voltage is applied through 2 circuits. Voltage flows through the turn signal switch circuit 1414 at terminal H of harness connector C216 and circuit 18 at terminal M of C216.

For circuit 1414, voltage flows through circuit 1414 to the instrument cluster for the left turn indicator, and to the daytime running lamps module. Voltage then flows through circuit 14 to the left front turn signal lamp.

For circuit 18, voltage flows through circuit 18 to the left rear turn signal lamp. Current flow heats the timing element in the hazard lamp/turn signal flasher. The timing element continuously opens and closes the circuit for the right turn signal lamps, circuit 1415 terminal J of C216 and circuit 19 terminal N of C216.

Voltage is applied when the ignition is in the RUN position through the TURN B/U Fuse in the fuse block, to the turn signal lamp flasher through circuit 141. Then voltage is applied from the flasher to the turn/hazard switch through circuit 16. 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 tail/stop/turn lamp through circuit 18. The LH tail/stop/turn lamp is grounded through circuit 1250. 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 tail/stop/turn lamp through circuit 19. The RH tail/stop/turn lamp is grounded through circuit 1250.

Voltage is applied at all times from the STOP/HAZARD fuse to the hazard lamp flasher through circuit 140. The current flow heats the timing element in the hazard lamp flasher. The voltage continuously opens and closes circuit 27 to the turn/hazard switch and then to all the turn signal lamps and both of the turn telltale lamps. All of the turn signal lamps and both of the turn telltale lamps flash on and off.

Voltage is applied at all times from the STOP/HAZARD fuse to the stop lamp switch through circuit 140. Voltage is applied from the stop lamp switch to the turn/hazard switch through circuit 20 when the brake pedal is depressed. The voltage turns on the left and the right tail/stop/turn signal lamps and the center high mounted stop lamp.