Pinpoint Test G: The AUTOLAMPS Are On Continuously

WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

G1 CHECK THE LCM HEADLAMP SWITCH PID
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: LCM Headlamp Switch PIDs.
- Monitor the LCM headlamp switch PIDs while moving the headlamp switch through all positions.
- Do the headlamp switch positions agree with the PIDs?
Yes : GO to G5.

No : GO to G2.
G2 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Key in OFF position.
- Disconnect: Headlamp Switch C205a.
- Measure the resistance between the headlamp switch C205a-7, circuit 57 (BK), harness side and ground.
  
  Fig 1: Measuring Resistance Between Headlamp Switch C205A-7, Circuit 57 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to G3.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
G3 CHECK THE HEADLAMP SWITCH
- Carry out the headlamp switch component test. Refer to COMPONENT TESTING .
- Is the headlamp switch OK?
Yes : GO to G4.

No : INSTALL a new headlamp switch. REFER to HEADLAMP SWITCH . CLEAR the DTCs. REPEAT the self-test.

G4 CHECK THE HEADLAMP SWITCH INPUT CIRCUITS FOR AN OPEN AND SHORT TO GROUND

Disconnect: LCM C2145a and C2145b.

Measure the resistance between the headlamp switch, harness side and the LCM, harness side; and between the headlamp switch, harness side and ground as follows:

HEADLAMP AND LCM CONNECTOR AND CIRCUIT

Headlamp Switch Connector-Pin	LCM Connector-Pin	Circuit
C205a-4	C2145a-15	220 (VT/OG)
C205a-9	C2145b-2	1400 (TN/WH)
C205a-5	C2145a-9	1032 (WH/BK)
C205a-10	C2145a-3	1033 (RD/YE)

Is the resistance less than 5 ohms between the headlamp switch and the LCM, and greater than 10,000 ohms between the headlamp switch and ground?

Yes : GO to G9.

No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

G5 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN
- Key in OFF position.
- Disconnect: Light Sensor C2228.
- Measure the resistance between the light sensor C2228-5, circuit 676 (PK/OG), harness side and ground.
  
  Fig 2: Measuring Resistance Between Light Sensor C2228-5, Circuit 676 (PK/OG), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to G6.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
G6 CHECK CIRCUIT 218 (WH/VT) FOR A SHORT TO VOLTAGE
- Disconnect: LCM C2145a.
- Key in ON position.
- Measure the voltage between the light sensor C2228-2, circuit 218 (WH/VT), harness side and ground.
  
  Fig 3: Measuring Voltage Between Light Sensor C2228-2, Circuit 218 (WH/VT), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
Yes : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

No : GO to G7.
G7 CHECK CIRCUIT 218 (WH/VT) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between the light sensor C2228-2, circuit 218 (WH/VT), harness side and the LCM C2145a-1, circuit 218 (WH/VT), harness side.
  
  Fig 4: Checking Circuit 218 (WH/VT) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to G8.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
G8 CHECK FOR VOLTAGE TO THE LIGHT SENSOR
- Connect: LCM C2145a.
- Key in ON position.
- Place the headlamp switch in the AUTOLAMPS ON position.
- Measure the voltage between the light sensor C2228-2, circuit 218 (WH/VT), harness side and ground.
  
  Fig 5: Measuring Voltage Between Light Sensor C2228-2, Circuit 218 (WH/VT), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage approximately 5 volts?
Yes : INSTALL a new light sensor. REFER to LIGHT SENSOR . CLEAR the DTCs. REPEAT the self-test.

No : GO to G9.
G9 CHECK FOR CORRECT LCM OPERATION
- Key in OFF position.
- Disconnect all the LCM connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the LCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes : INSTALL a new LCM. REFER to MULTIFUNCTION ELECTRONIC MODULES . TEST the system for normal operation.

No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.