Principles of Operation

WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: When installing a new smart junction box (SJB), it must be configured for this feature, if originally equipped. Refer to MODULE CONFIGURATION article.

NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).

The SJB controls the 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
Transaxle gear selection

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

NOTE: The DRL is not a programmable parameter for the Sable.

The SJB can be configured to turn the DRL on for the Taurus and Taurus X. Refer to MODULE CONFIGURATION article for additional information on this programmable parameter.