With Daytime Running Lights (DRL)

HEADLAMPS

With the LIGHT SWITCH in the OFF or PARK position and the engine running, Daytime Running Lights operation is achieved by applying system voltage from the GENERATOR, through the closed contacts of the Restart Relay, to the coils of Daytime Running Lights Relay-1, Daytime Running Lights Relay-3 and the Daytime Running Lights Cut Relay. The coils of Daytime Running Lights Relays-1 and -3 are provided a ground at G103 through the closed contacts of both the Daytime Running Lights Cut Relay (de-energized) and Daytime Running Lights Relay-2 (also de-energized).

With both voltage and ground provided to the coil of Daytime Running the relay is energize, the terminal 2-6 contacts close, and system voltage from FL-2 is applied through Fuses E-7 and E-8 to the HEADLAMPS.

With both voltage and ground provided to the coil of Daytime Running Lights Relay-1, the relay is energized, and the contacts are pulled to provide only the LOW-BEAM HEADLAMPS a ground at G103 through the DAYTIME RUNNING LIGHTS RESISTOR. Because of the DAYTIME RUNNING LIGHTS RESISTOR in the ground circuit, the LOW-BEAM HEADLAMPS operate at approximately 85 percent brilliance.

Whenever the parking brake is engaged, the coil of the Daytime Running Lights Cut Relay is provided a ground at the PARKING BRAKE SWITCH. With both voltage and ground provided, the Daytime Running Lights Cut Relay is energized, the contacts are pulled open, and the ground circuit for both Daytime Running Lights Relays-1 and - 3 is interrupted. In this manner, Daytime Running Lights operation is terminated whenever the parking brake is engaged.

As long as the engine is running and the LIGHT SWITCH is not in the HEAD position, Daytime Running Lights Relay-3 will remain energized. With this relay energized, its terminal 4-5 contacts are open and high- beam operation is disabled by interrupting the only possible ground circuit for the HIGH-BEAM HEADLAMPS.

With the LIGHT SWITCH in the HEAD position, the coil of Daytime Running Lights Relay-2 is provided a ground through the LIGHT SWITCH to G201. Because the coil is provided system voltage at all times through FL-2, Daytime Running Lights Relay-2 energizes, its terminal 1-2 contacts close, its terminal 4-5 contacts open, and voltage is applied to the coil of the Lighting Relay. Because the coil of the Lighting Relay is permanently grounded at G102, the relay energizes as soon as voltage is applied. When this relay energizes, its contacts close and voltage is applied through Fuses E-7 and E8 to the HEADLAMPS.

Because the 4-5 contacts of Daytime Running Lights Relay-2 are now open, the ground circuit for the coils of Daytime Running Lights Relay-1 and Daytime Running Lights Relay-3 is interrupted. This action causes the contacts of Daytime Running Lights Relay-1 to swing to their de-energized position. This position provides an unresisted ground through the LO contacts of the Dimmer/Passing Switch to G201 - causing the HEADLAMPS to light at full brilliance.

Whenever the Dimmer/Passing Switch is pulled back and released, the LO contacts open and the HI contacts close. Repeated action of the switch toggles the contact positions back and forth between LO and HI. With the HI contacts closed, the HIGH-BEAM HEADLAMPS are provided a ground at G201 through the closed contacts of Daytime Running Lights Relay-3 and the HI contacts of the Dimmer/Passing Switch.

When the Dimmer/Passing Switch is pulled back and held, the FTP (Flash-to-Pass) contacts are pulled closed. The FTP contacts ground the coil of Daytime Running Lights Relay-2 at G201. Because the coil receives voltage at all times from FL-2. Daytime Running Lights Relay-2 is energized as soon as the ground is provided. With the relay energized, its terminal 1-2 contacts close and voltage is applied to the coil of the Lighting Relay. Because the coil of Lighting Relay is permanently grounded at G102, the relay energizes as soon as voltage is applied. When energized, its terminal 2-4 contacts close and voltage is applied through Fuses E-7 and E-8 to the HEADLAMPS. Because a ground is provided at G201 through the FTP contacts in the Dimmer/Passing Switch, the HIGH-BEAM HEADLAMPS operate as soon as voltage is applied. Further, because pulling the Dimmer/Passing Switch always toggles the LO/HI contacts, one of two actions will occur. If the Dimmer/Passing Switch was in the LO position when it was pulled back, the LO contacts will open, the HI contacts will close, and only the HIGH- BEAM HEADLAMPS will operate when the FTP contacts are closed. If, however, the Dimmer/Passing Switch was in the HI position when pulled back, the HI contacts will open, the LO contacts will close, and because all of the HEADLAMPS are not provided both voltage and ground, they will all operate.

FOGLAMPS

System voltage is applied at all times to the terminal 2 contact of the (Fog Lamp) Relay. System voltage is also applied to the coil of the (Fog Lamp) Relay whenever the LIGHT SWITCH is in the HEAD position. When the FOG LAMP SWITCH is pressed to ON, a ground is provided to the coil of the (Fog Lamp) Relay. This ground is provided at G201 through the LO contacts of the Dimmer/Passing Switch. With both voltage and ground provided, the (Fog Lamp) Relay is energized, its terminal 2-4 contacts close, and voltage is applied to the FOG LAMPS. Because the FOG LAMPS are permanently grounded at G102 and G103, they operate as soon as voltage is applied.

Voltage to the (Fog Lamp) Relay is only available with the LIGHT SWITCH in the HEAD position, and a ground is only available with the Dimmer/Passing Switch in the LO position. Due to this configuration, FOG LAMP operation is possible only in conjunction with LOW-BEAM HEADLAMP operation. The FOG LAMP SWITCH has its own illumination and an integral LED indicator that lights whenever the FOG LAMPS are lit.