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Pinpoint Test O: The Air Conditioning (A/C) Is Always On - A/C Mode Always Commanded On

NOTE: When disconnecting and reconnecting the pressure transducer electrical connector, make sure that the connector-locking device is in place and that the locking device and connector are correctly and fully seated.
  1. O1 CHECK THE AIR CONDITIONING COMPRESSOR CYCLING SWITCH (ACCS) PCM PID WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: ACCS PCM PID
    • Press the OFF manual override buttons on the HVAC module - DATC and HVAC module - EATC or select OFF on the HVAC module - EMTC.
    • Does the ACCS PCM PID read ON? 
    1. YES  : DATC/EATC, go to  O2.

      EMTC, go to  O3.

    2. NO  : Go to  O6.
  2. O2 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_AC) HVAC PID WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: CC_AC HVAC PID
    • Does the CC_AC HVAC PID read DEPRESSED? 
    1. YES  : Go to  O5.
    2. NO  : Go to  O6.
  3. O3 CHECK EMTC A/C REQUEST OUTPUT 
    • Key in OFF position.
    • Disconnect: IC C220
    • Key in ON position.
    • Select the OFF position on the HVAC module - EMTC.
      • Fig 1: Checking EMTC A/C Request Output
      GF0041585Courtesy of FORD MOTOR CO.
    • Measure the resistance between IC C220-23, circuit CH434 (GY/YE), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  O4.
    2. NO  : Go to  O6.
  4. O4 CHECK CIRCUIT CH434 (GY/YE) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: HVAC module - EMTC C2357a
    • Key in ON position.
      • Fig 2: Checking Circuit CH434 (GY/YE) For A Short To Ground
      GF0041585Courtesy of FORD MOTOR CO.
    • Measure the resistance between IC C220-23, circuit CH434 (GY/YE), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  O5.
    2. NO  : REPAIR circuit CH434 (GY/YE) for a short to ground. TEST the system for normal operation.
  5. O5 CHECK THE MODULE CONNECTION 
    • Carry out the HVAC Module Cold Boot Process.
      • NOTE: DATC/EATC systems only.
    • Carry out the HVAC Module - Electronic Automatic Temperature Control (EATC) and HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self Test.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new HVAC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
    2. 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.
  6. O6 CHECK THE PCM CONNECTION 
    • Clear the DTCs.
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion.
      • pushed-out pins.
      • incorrectly seated connector.
    • Connect and correctly seat all the PCM connectors.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new PCM. TEST the system for normal operation.
    2. 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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