Principles Of Operation

Daytime Running Lamps (DRL)

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

NOTE: When installing a new SJB, it must be configured for this feature, if originally equipped. Refer to Module Configuration [1][2]Initial Inspection and Diagnostic Overview.

The SJB controls the Daytime Running Lamps (DRL) by using various inputs to determine whether or not the DRL should be illuminated. These inputs include:

- Ignition switch position
- Headlamp switch position
- Headlamps on or off
- Transmission gear selection

When the DRL is active, the SJB provides a pulse-width modulated voltage to the low beam headlamps. This illuminates the headlamps at a reduced intensity.

The SJB can be configured to turn the DRL on for this vehicle. Refer to Module Configuration [1][2]Initial Inspection and Diagnostic Overview for additional information on this programmable parameter.