Circuit/System Description

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The B10B Sun Load Temperature and Ambient Light and Security Indicator Sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 V and 4.9 V depending on outside lighting conditions. The K9 Body Control Module (BCM) provides a 5 V reference signal to the ambient light sensor and a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lamps or automatic lamp control when the S78 Turn Signal Switch is in the AUTO position. In daylight conditions, the BCM will send a serial data message to the K219 Lighting Control Module to command the daytime running lamps ON. During low light conditions the Lighting Control Module will command the low beam headlamps ON.