Pinpoint Test F: The HCM Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2010 Lincoln MKX and 2010 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to BATTERY, MOUNTING AND CABLES .

F1 CHECK THE HCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
NOTE: HCM testing is carried out at the LH headlamp assembly connector.
- Ignition OFF.
- Disconnect: LH Headlamp Assembly C1021b.
- Ignition ON.
- Measure the voltage between the LH headlamp assembly C1021b-3, circuit CBB51 (BN), harness side and ground.
  
  Fig 1: Measuring Voltage Between LH Headlamp Assembly C1021B-3, Circuit CBB51 (BN) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to F2 .
- No: VERIFY the Battery Junction Box (BJB) fuse 51 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS for Edge or SYSTEM WIRING DIAGRAMS for MKX to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.
F2 CHECK THE HCM GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the LH headlamp assembly C1021b-9, circuit GD120 (BK/GN), harness side and ground.
  
  Fig 2: Measuring Resistance Between LH Headlamp Assembly C1021B-9, Circuit GD120 (BK/GN) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to F3 .
- No: REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
F3 CHECK THE HS-CAN CIRCUITS BETWEEN THE HCM AND THE DLC FOR AN OPEN
- Measure the resistance between the LH headlamp assembly C1021b-6, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
  
  Fig 3: Measuring Resistance Between LH Headlamp Assembly C1021B-6, Circuit VDB04 (WH/BU) And DLC C251-6, Circuit VDB04 (WH/BU)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the LH headlamp assembly C1021b-12, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
  
  Fig 4: Measuring Resistance Between LH Headlamp Assembly C1021B-12, Circuit VDB05 (WH) And DLC C251-14, Circuit VDB05 (WH)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: CONNECT the negative battery cable. GO to F4 .
- No: REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
F4 CHECK FOR CORRECT HCM OPERATION
- Disconnect the HCM connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the HCM connector and make sure it seats correctly.
- Verify the concern is still present.
- Is the concern still present?
- Yes: INSTALL a new HCM . REFER to EXTERIOR LIGHTING . CLEAR the DTCs. REPEAT the network test with the scan tool.
  If the concern is still present, INSTALL a new LH headlamp assembly. REFER to EXTERIOR LIGHTING CLEAR the DTCs. REPEAT the network test with the scan tool.
- 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 network test with the scan tool.