Daytime Running Lamp: Description and Operation

DAYTIME RUNNING LAMPS (DRL)

The daytime running lamps (DRL) are controlled by the smart junction box (SJB) and utilize the existing circuitry in the vehicle.

The DRL feature operates the low beam headlamps at reduced intensity. This is accomplished by the SJB sending a pulse-width modulated voltage (PWM) to the low beam headlamps.

The DRL are turned on when the following conditions are met:
- the ignition switch is in the RUN position
- the high beams are not illuminated
- the parking brake is not engaged

PRINCIPLES OF OPERATION

Daytime Running Lamps (DRL) The daytime running lamps (DRL) are controlled by the smart junction box (SJB). It operates the low beam headlamps at a reduced intensity. The DRL driver (integral to the SJB) supplies pulse-width modulated (PWM) voltage, approximately 75% - 92% of battery voltage, to the low beam headlamps when the following conditions are met:
- the high beam headlamps are disabled.
- the ignition switch is in the RUN position.
- the parking brake switch is not engaged.