Normal Operation

WARNING: This page is about a different car, the 2006 Mercury Montego, 2006 Ford Freestyle, and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

The smart junction box (SJB) sends voltage reference signals to the headlamp switch through circuits 1400 (TN/WH), 1401 (BK/LG), 1402 (RD/WH) and 1399 (DB/WH). At any given time, one voltage reference signal is routed to ground by the headlamp switch, to circuit 1205 (BK), to indicate the headlamp switch position.

The SJB also sends a reference signal to the light sensor through circuit 1416 (YE/WH). When the headlamp switch is placed in the AUTOLAMPS ON position, the SJB monitors the ambient light conditions based on the input received from the light sensor. When the ambient light level has reached a point (determined by the internal programming of the SJB), the SJB provides voltage to the headlamps, parking and license plate lamps. Ground for the light sensor is provided through circuit 1205 (BK).