Automatic Headlight Sensor Circuit
2000-2003 Ford Excursion 7.3L V8 Power Stroke Diesel
Description
Malfunction in the automatic headlight ambient light sensor circuit.
Symptoms
- Auto headlights not turning on in tunnels/darkness
- Headlights on in bright daylight
- Auto headlight feature disabled
- Dash light sensor not adjusting brightness
Common Causes
- Faulty ambient light sensor
- Sensor covered by dashboard object
- Wiring damage
- BCM auto-light module fault
- Sensor window dirty
Diagnostic Steps
- Check light sensor reading with scan tool
- Clean sensor lens on dashboard
- Inspect sensor wiring
- Test BCM auto headlight output
- Verify feature is enabled in settings
Repair Notes
Replace ambient light sensor or clean sensor window. Check that nothing is covering the sensor on the dash top.
Related Codes
Other Body Codes
- B0001Driver Frontal Stage 1 Deployment Control
- B0002Driver Frontal Stage 2 Deployment Control
- B0003Passenger Frontal Stage 1 Deployment Control
- B0004Passenger Frontal Stage 2 Deployment Control
- B0005Driver Knee Airbag Deployment Circuit
- B0006Passenger Knee Airbag Deployment Circuit
- B0010Driver Side Airbag Deployment
- B0011Driver Side Airbag Deployment Circuit Open
- B0012Driver Side Airbag Deployment Circuit Short to Ground
- B0013Driver Side Airbag Deployment Circuit Short to Battery
B2100 on Other Vehicles
Ford Bronco
2021-2024 2.3L I4 EcoBoost
Ford Bronco
2021-2024 2.7L V6 EcoBoost
Ford Bronco Raptor
2022-2024 3.0L V6 EcoBoost
Ford Bronco Sport
2021-2024 1.5L I3 EcoBoost
Ford Bronco Sport
2021-2024 2.0L I4 EcoBoost
Ford Crown Victoria
1998-2011 4.6L V8 Modular 2V
Ford E-150
1997-2014 4.6L V8 Triton
Ford E-150
1997-2014 5.4L V8 Triton
Common Questions
What does code B2100 mean on a 2000-2003 Ford Excursion?
B2100 stands for "Automatic Headlight Sensor Circuit". Malfunction in the automatic headlight ambient light sensor circuit.
What are the symptoms of B2100 on a Ford Excursion?
Common symptoms of B2100 include: Auto headlights not turning on in tunnels/darkness, Headlights on in bright daylight, Auto headlight feature disabled, Dash light sensor not adjusting brightness.
What causes B2100 on a 2000-2003 Ford Excursion?
Common causes of B2100 include: Faulty ambient light sensor, Sensor covered by dashboard object, Wiring damage, BCM auto-light module fault, Sensor window dirty.