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Pinpoint Test J: The Air Conditioning (A/C) Is Always On

WARNING: This page is about a different car, the 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
  1. J1 CHECK PID WACF WITH THE A/C OFF 
    • Key in ON position.
    • Place the function selector switch to the OFF position or press the OFF manual override button on the EATC module.
    • Enter the following diagnostic mode on the diagnostic tool: PCM PID WACF
    • Does the PCM PID WACF read YES? 
    1. YES  : REPAIR circuit 331 (PK/YE) for a short to ground. TEST the system for normal operation.
    2. NO  : Go to  J2.
  2. J2 CHECK PID ACCS WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: PCM PID ACCS
    • Does the PCM PID ACCS read ON? 
    1. YES  : Go to  J3.
    2. NO  : Go to  J7.
  3. J3 CHECK FOR VOLTAGE AT THE A/C CYCLING SWITCH 
    • Key in OFF position.
    • Disconnect: A/C Cycling Switch C1081
    • Key in ON position.
      • Fig 1: Checking Circuit For Voltage
      G03889919Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C cycling switch C1081-4, circuit 348 (VT) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  J4.
    2. NO  : Go to  J5.
  4. J4 CHECK CIRCUIT 348 (VT) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: Function Selector Switch C294a or EATC module C228b
    • Key in ON position.
      • Fig 2: Checking Circuit For Voltage
      G03889919Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C cycling switch C1081-4, circuit 348 (VT) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit 348 (VT) for a short to voltage. TEST the system for normal operation.
    2. NO  : INSTALL a new function selector switch (manual A/C), or INSTALL a new EATC module (EATC). REFER to CLIMATE CONTROL article. TEST the system for normal operation.
  5. J5 CHECK CIRCUIT 441 (RD/YE) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: A/C Pressure Cutoff Switch C1078
    • Key in ON position.
      • Fig 3: Checking Circuit For Voltage
      GF0007945Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C pressure cutoff switch C1078-1, circuit 441 (RD/YE) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit 441 (RD/YE) for a short to voltage. TEST the system for normal operation.
    2. NO  : Go to  J6.
  6. J6 CHECK CIRCUIT 439 (TN/LG) FOR A SHORT TO VOLTAGE 
      Fig 4: Checking Circuit For Voltage
      GF0007946Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C pressure cutoff switch C1078-3, circuit 439 (TN/LG) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit 439 (TN/LG) for a short to voltage. TEST the system for normal operation.
    2. NO  : INSTALL a new PCM. TEST the system for normal operation.
  7. J7 CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Key in OFF position.
    • Disconnect: A/C Compressor Clutch Field Coil C100
    • Key in ON position.
      • Fig 5: Checking Circuit For Voltage
      GF0007937Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C compressor clutch field coil C100-1, circuit 321 (GY/WH) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  J8.
    2. NO  : ADJUST the A/C compressor clutch air gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment . TEST the system for normal operation.
  8. J8 CHECK CIRCUIT 321 (GY/WH) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: A/C Control Relay
    • Key in ON position.
      • Fig 6: Checking Circuit For Voltage
      GF0007937Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C compressor clutch field coil C100-1, circuit 321 (GY/WH) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit 321 (GY/WH) for a short to voltage. TEST the system for normal operation.
    2. NO  : INSTALL a new A/C control relay. CHECK the A/C clutch diode. INSTALL a new diode, if necessary. TEST the system for normal operation.
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