Headlights Circuit Description

The ambient light sensor is supplied a reference ground from the Instrument Panel Integration Module (IPM). The sensor is a light sensitive variable resistor that varies resistance as the outside ambient light level changes. The IPM receives an input voltage proportional to the resistance of the resistor. The IPM sends a Class 2 message to the dash Integration Module (DIM) and the Rear Integration Module (RIM) indicating the daytime/nighttime status. The DIM uses the daytime/nighttime status of the ambient light sensor to automatically turn on and off the headlamps with the twilight sentinel on. The RIM uses the daytime/nighttime status of the ambient light sensor to automatically turn on and off the interior courtesy lamps with the interior lamp switch in the AUTO position.