Daytime Running Lamp: Description and Operation

DAYTIME RUNNING LAMPS (DRL)

The daytime running lamp (DRL) system operates the headlamps at a reduced intensity due to the DRL resistor when the following conditions are met:
- The high beam headlamps are disabled.
- The ignition switch is in the RUN position.
- The headlamp switch is in the OFF position.
- The parking brake is not engaged.

The DRL system consists of:
- daytime running lamp relays (located in the engine compartment)
- the daytime running lamp resistor (located near the LH headlamp)

PRINCIPLES OF OPERATION

The daytime running lamps (DRL) are implemented by using the low beams at a reduced voltage of approximately 80% system voltage. This is accomplished by inserting a resistor in series with the low beam filaments. When the headlamp switch is engaged, the daytime running lamp function is disabled and the low beam filaments receive 100% system voltage.