Pinpoint Test D: The Headlamps 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.

D1 DETERMINE IF THE HIGH BEAMS ARE ILLUMINATED
- Key in OFF position.
- Place the headlamp switch in the HEADLAMPS ON position.
- Place the multifunction switch in the FLASH-TO-PASS position.
- Does the headlamp brightness increase?
Yes : GO to D6.

No : GO to D2.
D2 CHECK THE MULTIFUNCTION SWITCH
- Key in OFF position.
- Disconnect: Multifunction Switch C202c.
- Do the high beam headlamps continue to illuminate?
Yes : GO to D3.

No : INSTALL a new multifunction switch. REFER to STEERING COLUMN SWITCHES . CLEAR the DTCs. REPEAT the self-test.
D3 CHECK CIRCUITS 1337 (VT/YE) AND 1335 (YE/WH) FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: LCM 2145c.
- Do the high beam headlamps continue to illuminate?
Yes : REPAIR circuit 1337 (VT/YE) (LH high beam) or circuit 1335 (YE/WH) (RH high beam). CLEAR the DTCs. REPEAT the self-test.

No : GO to D4.
D4 CHECK CIRCUIT 12 (LG/BK) FOR A SHORT TO GROUND
- Place the headlamp switch in the OFF position.
- Disconnect: LCM J2145d.
- Measure the resistance between the multifunction switch C202c-10, circuit 12 (LG/BK), harness side and ground.
  
  Fig 1: Measuring Resistance Between Multifunction Switch C202C-10, Circuit 12 (LG/BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes : GO to D5.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
D5 CHECK CIRCUIT 12 (LG/BK) FOR A SHORT TO VOLTAGE
- Place the headlamp switch in the OFF position.
- Key in ON position.
- Measure the voltage between the multifunction switch C202c-10, circuit 12 (LG/BK), harness side and ground.
  
  Fig 2: Measuring Voltage Between Multifunction Switch C202C-10, Circuit 12 (LG/BK), 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 D13.
D6 CHECK THE LCM HEADLAMP SWITCH PIDs
- Place the headlamp switch in the OFF position.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: LCM Headlamp Switch PIDs.
- Monitor the LCM headlamp switch status PIDs while moving the headlamp switch through all positions.
- Do the headlamp switch PIDs agree with the headlamp switch position?
Yes : For non-police vehicles, GO to D7.

For police vehicles, GO to D10.

No : GO to D11.
D7 CHECK THE LCM WINDSHIELD WIPER MOTOR PID
- Place the headlamp switch in the OFF position.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: LCM Windshield Wiper Motor PID.
- Monitor the LCM windshield wiper motor status PID.
- Does the PID indicate the windshield wiper motor is active?
Yes : GO to D8.

No : GO to D10.
D8 CHECK THE WINDSHIELD WIPER MOTOR
- Key in OFF position.
- Disconnect: Windshield Wiper Motor C125.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: LCM Windshield Wiper Motor PID.
- Monitor the LCM windshield wiper motor status PID.
- Does the PID indicate the windshield wiper motor is active?
Yes : GO to D9.

No : INSTALL a new windshield wiper motor. REFER to WIPERS AND WASHERS . CLEAR the DTCs. REPEAT the self-test.
D9 CHECK CIRCUIT 28 (BK/PK) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: LCM C2145d.
- Measure the resistance between the LCM C2145d-14, circuit 28 (BK/PK), harness side and ground.
  
  Fig 3: Measuring Resistance Between LCM C2145D-14, Circuit 28 (BK/PK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
Yes : GO to D13.

No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
D10 CHECK CIRCUITS 160 (DB/WH) AND 161 (DG/OG) FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: LCM J2145c and C2145d.
- Key in ON position.
- Do the low beam headlamps continue to illuminate?
Yes : REPAIR circuit 160 (DB/WH) (LH low beam) or circuit 161 (DG/OG) (RH low beam). CLEAR the DTCs. REPEAT the self-test.

No : GO to D13.
D11 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 4: 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 D12.

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

D12 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 (if equipped with autolamps)	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 D13.

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

D13 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.