Daytime Running Lamps (DRL) without HID RPO TT4
The daytime running light bulbs are combined with the park lamps. One filament is for the daytime running light and one for the park lamps. The daytime running lights will operate when the following conditions are met:
- Engine is running.
- Headlamp switch in AUTOMATIC LIGHT position.
- The high and low beam headlamps are OFF.
By turning the headlamp switch in the OFF position the automatic light function and the daytime running lights will be deactivated.
With CE1
The rain/ambient light sensor module is used to monitor outside lighting conditions. The rain/ambient light sensor module provides a serial data message to the BCM based on outside lighting conditions to determine if outside lighting conditions are correct for either daytime running lights or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the designated daytime running lights ON. During low light conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel daytime running lights operation.
Without CE1
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2-4.9 V depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5 V reference signals to the ambient light sensor. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights or low beam when the headlamp switch is in the AUTOMATIC LIGHT position. In daylight conditions, the BCM will command the daytime running lights ON by applying ground to the left and right daytime running light relays via separate left and right daytime running light relay control circuits. When the BCM applies ground to the relay control circuits, the left and right daytime running light relay coils energize causing both relay switch contacts to close. With the left and right daytime running light relay switch contacts closed, battery voltage flows to the left and right daytime running lights. Any function or condition that turns on the headlamps will cancel daytime running lights operation.