The sensor is on top of the dash pad
The relay, the book says, is at the underhood junction box on the left side of the engine compartment (passenger side).
Here's a general description of the system:
Daytime running lamps (DRL)
are standard on all vehicles that are sold in Canada and the United
States. The DRLs improve the visibility of the vehicle when viewed from
the front in daylight. The normal DRL system utilizes the headlamps at
a reduced voltage. Apply the parking brake or place the gear selector
in PARK in order to override the DRL feature. The DRLs are fully active
and unaffected by any further operation of the park brake under the
- With the ignition switch ON
- With the parking brake OFF
- The gear selector is not in the PARK position
Battery voltage is applied to the headlamp bulbs at all times. The headlamps are controlled by supplying the ground for the lamps through the turn/headlamp switch assembly. When the turn/headlamp switch is in the ON position, the ground is supplied through CKT 150.
The body control module (BCM) controls the daytime running lamps (DRL) . The system allows the high beam headlamps to operate at a reduced intensity when the following conditions exist:
- The engine is running. The park brake is off.
- The transaxle is not in the PARK position.
- The normal headlamps are turned OFF.
The BCM turns
on the system by grounding CKT 592. This action energizes the DRL
relay. This condition allows a reduced voltage across the headlamps by
placing both high beam headlamps in series with each other. When the headlamp switch is turned ON, the headlamps operate normally.
The park brake provides an input to the BCM. When the park brake is in
the ON position, the daytime running lamps remain disabled until the
park brake is moved to the OFF position or the vehicle speed is above 3 mph .
The fog lamp switch provides an input to the BCM. The BCM enables the fog lamp relay under the following conditions:
- The BCM receives an ON request input from the fog lamp switch.
- The ignition switch is in the ON position.
- The headlamp switch is in the PARK or HEAD position.
When the headlamp switch
is in the HEAD position, ensure that the high/low beam switch is the
LOW position in order for the BCM to enable the fog lamp relay.
The BCM controls the headlamps and the park lamps by energizing the automatic lamp control relay. The BCM uses an ambient light sensor for the following reasons:
- In order to determine available light levels
- In order to determine when to energize the automatic lamp control relay
The BCM energizes the park lamp relay in order to turn ON the exterior lamps.