Headlamps
Battery voltage is applied continuously to the headlamp switch through
circuit 3240. When the headlamp switch is in the HEAD position, voltage
is applied to the headlamp dimmer switch.
When the headlamp dimmer switch is in the LOW position, battery voltage
is applied to the following components through circuit 12:
• | The underhood accessory wiring junction block |
When the headlamp dimmer switch is in the HIGH position, battery voltage
is applied to the following components through circuit 11:
• | The underhood accessory wiring junction block |
• | The high beam headlamps |
Automatic Headlamps
The automatic headlamps control module is designed to automatically
operate the exterior lights depending on the outside light conditions.
The automatic headlamp control module operates when low light is detected,
• | The ignition switch is in the RUN position. |
In low light the ambient light sensor detects darkness, turning on the
low beam headlamps to full intensity through circuit 10. Additionally the
auto headlamp control module turns on the following lamps through circuit
74:
If the engine stalls with the automatic head lamp control module in
the low light mode, the automatic headlamp control module turns OFF the headlamps
while the engine is being cranked. The automatic headlamp control module
turns ON the following lamps while the engine is being cranked:
The following lamps operate in the usual manner:
• | The instrument panel lamp dimmer switch |
The automatic headlamp control module receives voltage from the following
fuses:
• | Fuse D6 -- D7 through circuit 1239 |
• | Fuse B3 -- B4 through circuit 41 |
The following lamps may be operated manually at any time by using the
headlamp and the instrument panel lamp dimmer switch:
The automatic headlamp module does not operate if the system voltage
is less than 9 volts or greater than 18 volts.
Ambient Light Sensor
The ambient light sensor is a light sensitive variable resistor. The
ambient light sensor's resistance decreases as the outside light intensity
increases. The automatic headlamp control module performs the following functions:
• | Measures the voltage drop across the ambient light sensor. |
• | Determines whether the ambient light sensor should operate in
the low light mode. |
Park Brake Input
The automatic headlamp control module will not operate any headlamps
or exterior lamps if the park brake is applied before the ignition switch
is turned to the RUN position. This allows the driver to start the vehicle
and keep the headlamps OFF, as long as the park brake is applied. The automatic
headlamp control module activates the headlamps when the park brake is released
with the ignition switch in the RUN position. This feature functions only
when the park brake is applied before the ignition switch is turned to the
RUN position. The headlamps will not turn OFF, if the park brake is applied
after the ignition switch is turned to the RUN position.