Ambient Light Sensor
Table of contents
B1A85 LINCOLN Possible Causes
- Faulty Ambient Light Sensor
- Ambient Light Sensor harness is open or shorted
- Ambient Light Sensor circuit poor electrical connection
- Faulty Steering Column Control Module (SCCM)
- Faulty Body Control Module (BCM)
How do I fix code B1A85 LINCOLN?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- B1A85:11 Ambient Light Sensor Circuit Short To Ground
- B1A85:13 Ambient Light Sensor Circuit Open
Cost of diagnosing the B1A85 LINCOLN code
The cost of diagnosing the B1A85 LINCOLN code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B1A85 LINCOLN Description
The Steering Column Control Module (SCCM) sends voltage signals to the headlamp switch through the headlamp switch input circuits (off, parking lamps, headlamps, autolamps). At any given time, the headlamp switch routes one of the input circuits to ground, indicating the headlamp switch position to the SCCM .
The SCCM sends the status of the headlamp switch position to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN).
The autolamp feature is enabled when the BCM receives a message from the SCCM indicating the headlamp switch in the AUTOLAMPS ON position.
When the BCM enables the autolamps feature, the BCM monitors the light sensor input. The light sensor determines the amount of light based on the input received from the ambient lighting conditions. When the ambient level has reached a point (determined by the internal programming of the BCM ), the BCM provides voltage to the exterior lamps.
If the SCCM detects multiple or no active headlamp switch inputs, it sends a message to the BCM to indicate a fault with the headlamp switch input.