Ford Explorer Quiz
Electrical

Diagnosis and Testing - Headlamps

In this manual: Electrical
General Information — 41Chassis — 173Powertrain — 250Electrical — 303Body and Paint — 331
~4min read

Diagnostic Trouble Code (DTC) Chart

The diagnosis in this manual assumes a certain level of skill and knowledge of Ford-approved diagnostic procedures.
REFER TO: Diagnostic Methods (100-00 General Information, Description and Operation).


Diagnostic Trouble Code Chart


Module Trouble Code Description Action
BCM B1A85:11 Ambient Light Sensor: Short to Ground GO to Pinpoint Test A
BCM B1A85:13 Ambient Light Sensor: Circuit Open GO to Pinpoint Test A
BCM — All Other BCM Diagnostic Trouble Codes (DTCs)
REFER TO: Body Control Module (BCM) (419-10 Multifunction Electronic Modules, Diagnosis and Testing).

Symptom Charts

Symptom Chart: Headlamps

The diagnosis in this manual assumes a certain level of skill and knowledge of Ford-approved diagnostic procedures.
REFER TO: Diagnostic Methods (100-00 General Information, Description and Operation).

Condition Possible Sources Action
Module Does Not Respond to Diagnostic Scan Tool
  • Fuse
  • Wiring, Terminals or Connectors
  • Module
REFER TO: Communication Network (418-00 Communication Network, Diagnosis and Testing).
Headlamps Do Not Operate or Operate Incorrectly Refer to Pinpoint Test GO to Pinpoint Test A

Pinpoint Tests


DIAGNOSTIC TEST A: HEADLAMPS DO NOT OPERATE OR OPERATE INCORRECTLY

For circuits and connector information, refer to Wiring Diagrams, Cell 86.

Normal Operation and Fault Symptoms

REFER TO: Exterior Lighting - Overview (417-01 Exterior Lighting, Description and Operation).
REFER TO: Exterior Lighting - System Operation and Component Description (417-01 Exterior Lighting, Description and Operation).

DTC Fault Trigger Conditions

Trouble Code Description Fault Trigger Condition
BCM B1A85:11 Ambient Light Sensor: Short to Ground Continuous memory and on-demand DTC that is set when the BCM detects a short to ground in the light sensor input circuit.
BCM B1A85:13 Ambient Light Sensor: Open Circuit On-demand DTC that is set when the BCM detects an open in the light sensor input circuit.

Possible Sources

  • Light Sensor
  • Wiring, Terminals or Connectors
  • BCM

Visual Inspection and Pre-checks

  • Inspect the headlamp switch for damage.
  • Inspect the light sensor for damage.
A1 CHECK HEADLAMP MANUAL OPERATION
  • Turn the headlamp switch to HEADLAMPS, then OFF.

Do the headlamps operate normally?
Yes GO to A2
No
REFER TO: Headlamps (417-01 Exterior Lighting, Diagnosis and Testing).
A2 CHECK THE LIGHT SENSOR VOLTAGE
  • Ignition OFF.
  • Disconnect: Auto Lamp/Solar Load Sensor C286.
  • The ignition is on.
  • Turn the headlamp switch to AUTO LAMPS.
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-2 Ground

Is the voltage approximately 5 volts?
Yes GO to A3
No If the voltage is low, GO to A5.
If the voltage is high, GO to A7.
A3 CHECK THE LIGHT SENSOR FOR A SHORT TO GROUND
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-2 C286-4

Is the voltage approximately 5 volts?
Yes INSTALL a new auto lamp/solar load sensor.
REFER TO: Light Sensor (417-01 Exterior Lighting, Removal and Installation).
No GO to A4
A4 CHECK THE LIGHT SENSOR GROUND CIRCUIT FOR AN OPEN
  • Ignition OFF.
  • Disconnect: BCM C2280B.
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-4 C2280B-22

Is the resistance less than 3 ohms?
Yes GO to A8
No REPAIR the circuit.
A5 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO GROUND
  • Ignition OFF.
  • Disconnect: BCM C2280B.
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-2 Ground

Is the resistance greater than 10000 Ohms?
Yes GO to A6
No REPAIR the circuit.
A6 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR AN OPEN
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-2 C2280B-24

Is the resistance less than 3 ohms?
Yes GO to A8
No REPAIR the circuit.
A7 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO VOLTAGE
  • Ignition OFF.
  • Disconnect: BCM C2280B.
  • The ignition is on.
  • Action:
    Click to display the connectors
    Positive lead Measurement/Action Negative lead
    C286-2 Ground

Is there voltage present?
Yes REPAIR the circuit.
No GO to A8
A8 CHECK BCM (BODY CONTROL MODULE) OPERATION
  • Disconnect and inspect the BCM and all related inline connectors.
  • Repair:
    • corrosion (install new connector or terminals - clean module pins)
    • damaged or bent pins - install new terminals/pins
    • backed-out pins - install new pins as necessary
  • Reconnect the BCM and all related inline connectors. Make sure they are installed and fully seated.
  • Operate the system and determine if the concern is still present.

Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, STOP this test and FOLLOW the service article instructions. If no service articles apply, INSTALL a new BCM.
REFER to: Body Control Module (BCM) (419-10 Multifunction Electronic Modules, Diagnosis and Testing).
No The system is currently operating correctly. The concern may have been caused by module connections. ADDRESS the root cause of any connector or terminal issues.

Test yourself

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