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 current source that varies as the outside ambient light level changes. The IPM receives an input voltage proportional to the current of the sensor. 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 turn on and off the automatic interior courtesy lamps function with the interior lamp switch in the AUTO (off) position.