The headlamps are controlled by the following components:
| • | The Daytime Running Lamps (DRL) Control Module |
| • | The light switch |
| • | The dimmer switch |
When the light switch in is the HEAD position (the headlamps are ON), the following conditions occur:
Dimmer Switch LO
When the dimmer switch is in the LO position, the following components provide ground to the low beam filaments in the headlamps:
| • | The dimmer switch |
| • | The closed contacts of the light 2 relay to G201 |
Because the headlamp fuses supply voltage to the headlamps at all times, the low beam filaments will light.
Dimmer Switch HI
When the dimmer switch is in the HI position, the following components provide ground to the high beam filaments in the headlamps:
| • | The junction block |
| • | The dimmer switch |
| • | The closed contacts of the light 2 relay to G201 |
Because the headlamp fuses supply voltage to the headlamps at all times, the high beam filaments will light.
Ground to the high beam indicator is provided in the same manner as the high beam filaments. Because the left headlamp fuse supplies voltage to the high beam indicator at all times, the indicator will also light.
Dimmer Switch in PASS
When the dimmer switch is in the PASS position, the following components provide ground to the high beam filaments in the headlamps:
| • | The junction block |
| • | The dimmer switch |
| • | Back through the junction block to G203 |
Because the headlamp fuses supply voltage to the headlamps at all times, the high beam filaments will light.
Ground to the high beam indicator is provided in the same manner as the high beam filaments. Because the left headlamp fuse supplies voltage to the high beam indicator at all times, the indicator will also light.
Ignition Switch is ON
With the ignition switch in the ON/START position, voltage is applied to the DRL control module through the IG-COIL fuse. The DRL control module is permanently grounded to G201.
In order for the daytime running lamps to work properly, the following conditions must occur:
| • | The parking brake is disengaged. |
| • | The DRL control module does not receive a ground signal from the generator. (A ground signal from the generator indicates that the generator is not charging the battery.) |
| • | The light switch is in the OFF/PARK position. |
When the parking brake is engaged, the parking brake switch closes providing a ground to the DRL module. This disables the DRL operation.
When the generator is not running, a switch in the generator closes providing a ground to the DRL module. This disables the DRL operation.
When the light switch is in the HEAD position, a path to G201 is provided to the coil of the light 2 relay and to the DRL control module to G201. This disables the DRL operation.
When all of the listed conditions for the DRL operation occur, the DRL control module provides a ground for the low beam filaments in the headlamps through the DRL control module to G201. Because the headlamp fuses supply voltage to the headlamps at all times, the low beam filaments will light at 80% intensity.
The DRL control module also provides ground to the daytime running lamps indicator when the DRL is operating. Because the IG-COIL fuse applies voltage to the indicator, the indicator will light.
