Normal Operation

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

With the headlamp switch turned to the autolamp position, a battery voltage signal is sent to the vehicle security module through circuit 1399 (DB/WH). The vehicle security module then determines the amount of ambient light based on the input received from the photocell sensor. The input signal is received through circuit 218 (WH/VT). When the ambient level has reached a point (determined by the internal programming of the vehicle security module), two internal relays are energized to supply power to the exterior lamps. Circuit 196 (DB/OG) supplies power to the internal headlamp relay, which in turn supplies power to circuit 13 (RD/BK) when energized. Circuit 195 (TN/WH) supplies power to the internal parking lamp relay, which in turn supplies power to circuit 14 (BN) when energized. Circuit 1205 (BK) is the ground circuit for the photocell sensor.