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Pinpoint Test L: The Air Conditioning (A/C) Is Inoperative

NOTE: It is important to install relays in their correct position in the Battery Junction Box (BJB). Installing a relay incorrectly may cause wiring shorts or damage to modules. While carrying out diagnostics on relays, have only one BJB relay removed at a time. Failure to follow these instructions may result in damage to the vehicle circuitry or to control modules.
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC CHART .
NOTE: Some HVAC DTCs may inhibit A/C operation. If any HVAC DTCs are retrieved, diagnose those first. Refer to the HVAC MODULE DTC CHART .
NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), refer to FLUORESCENT DYE LEAK DETECTION .
  1. L1 CHECK THE A/C PRESSURE SENSOR (ACP_PRESS) PCM PID 
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: ACP_PRESS PCM PID.
    • With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the ACP_PRESS PID.
    • Are the pressure values of the manifold gauge set and the ACP_PRESS PID similar? 
    • Yes  : GO to L2.
    • No  : INSTALL a new A/C pressure transducer. TEST the system for normal operation.
  2. L2 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) HVAC PID 
    • Allow the vehicle exterior and interior to stabilize to an ambient temperature above 16°C (60°F).
    • Enter the following diagnostic mode on the scan tool: EVAP_TEMP HVAC PID.
    • Does the EVAP_TEMP HVAC PID read similar to the ambient temperature? 
    • Yes  : GO to L3.
    • No  : INSTALL a new A/C evaporator discharge temperature sensor. TEST the system for normal operation.
  3. L3 CHECK THE A/C INDICATOR WITH THE A/C ON 
    NOTE: Before carrying out this test step, be sure all other FCIM button functions are operational. If all other buttons operate correctly, continue with this test step. If multiple buttons are inoperative and DTC U0256:87 is not present, INSTALL a new FCIM  . TEST the system for normal operation. If DTC U0256:87 is present, diagnose the DTC first.
    • Select PANEL press the A/C button on the HVAC module.
    • Does the A/C indicator illuminate when the A/C button is pressed? 
    • Yes  : GO to  L5.
    • No  : If the vehicle is equipped with next generation navigation, GO to L4.

      If the vehicle is not equipped with next generation navigation, INSTALL a new FCIM  . TEST the system for normal operation.

  4. L4 CHECK THE MAX A/C OPERATION 
    NOTE: Before carrying out this test step, be sure all other ACM touch screen functions are operational. If all other touch screen functions operate correctly, continue with this test step. If multiple touch screen functions are inoperative and DTC U0163:87 is not present, INSTALL a new ACM. TEST the system for normal operation. If DTC U0163:87 is present, diagnose the DTC first.
    • Select MAX A/C on the next generation navigation screen.
    • Does the A/C operate when MAX A/C is selected? 
    • Yes  : INSTALL a new FCIM  . TEST the system for normal operation.
    • No  : GO to  L11.
  5. L5 CHECK THE AIR CONDITIONING CLUTCH (WAC/ACCR) PCM PID WITH THE A/C ON 
    • Enter the following diagnostic mode on the scan tool: WAC/ACCR PCM PID.
    • Does the WAC/ACCR PCM PID read ON? 
    • Yes  : GO to L6.
    • No  : GO to  L12.
  6. L6 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Ignition OFF.
    • Disconnect: A/C Compressor Clutch Field Coil C100.
    • Ignition ON.
    • Select PANEL and A/C on the HVAC module.
    • With the engine running, measure the voltage between A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH), harness side and ground.
      Fig 1: Measuring Voltage Between A/C Compressor Clutch Field Coil C100-1, Circuit CH401 (VT/WH), Harness Side And Ground
      G06064573Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : GO to L7.
    • No  : GO to  L9.
  7. L7 CHECK THE GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Ignition OFF.
    • Measure the resistance between A/C compressor clutch field coil C100-2, circuit GD120 (BK/GN), harness side and ground.
      Fig 2: Measuring Resistance Between A/C Compressor Clutch Field Coil C100-2, Circuit GD120 (BK/GN), Harness Side And Ground
      G06064574Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to L8.
    • No  : REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
  8. L8 CHECK THE A/C COMPRESSOR CLUTCH AIR GAP 
    • Measure the A/C compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C compressor clutch pulley.
      Fig 3: Measuring A/C Compressor Clutch Air Gap
      G06064575Courtesy of FORD MOTOR CO.
    • Is the A/C compressor clutch air gap average greater than 0.65 mm (0.030 in)? 
  9. L9 CHECK THE A/C CLUTCH RELAY FOR VOLTAGE 
    • Ignition OFF.
    • Disconnect: A/C Clutch Relay.
    • Ignition ON.
    • Measure the voltage between the A/C clutch relay socket, circuit SBB24 (VT/RD) and ground.
      Fig 4: Measuring Voltage Between A/C Clutch Relay Socket, Circuit SBB24 (VT/RD) And Ground
      G06064576Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : GO to L10.
    • No  : VERIFY Battery Junction Box (BJB) fuse 24 (10A) is OK. If OK, REPAIR circuit SBB24 (VT/RD) for an open. TEST the system for normal operation. If not OK, REFER to the appropriate Systems Wiring Diagram to identify the possible causes of the circuit short.
  10. L10 CHECK CIRCUIT CH401 (VT/WH) FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between the A/C clutch relay socket, circuit CH401 (VT/WH) and A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH), harness side.
      Fig 5: Measuring Resistance Between A/C Clutch Relay Socket And A/C Compressor Clutch Field Coil C100-1
      G06064577Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : CARRY OUT the A/C clutch relay component test. If the relay tests OK, GO to  L12.
    • No  : REPAIR circuit CH401 (VT/WH) for an open. TEST the system for normal operation.
  11. L11 CHECK THE MODULE CONNECTION 
    • Carry out the HVAC Module Cold Boot Process.
    • Carry out the HVAC Module On-Demand Self Test.
    • Operate the system.
    • Does the concern return? 
    • Yes  : INSTALL a new HVAC module. REFER to CLIMATE CONTROL . 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. TEST the system for normal operation.
  12. L12 CHECK THE PCM CONNECTION 
    • Clear the DTCs.
    • Disconnect all of the PCM connectors.
    • Check for:
      • corrosion.
      • pushed-out connectors.
      • incorrectly seated connector.
    • Connect and correctly seat all of the PCM connectors.
    • Operate the system.
    • Does the concern return? 
    • Yes  : INSTALL a new PCM. 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.
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