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HOMESERVICE MANUALSMERCURY2009MILAN PREMIER, 3.0 1, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1281 (HVAC CLIMATE CONTROL SYSTEM - GENERAL INFORMATION & DIAGNOSTICS)DIAGNOSTIC TESTSCLIMATE CONTROL SYSTEMSYMPTOM CHART - CLIMATE CONTROL SYSTEMS
2009 Mercury Milan Premier, 3.0 1, AWD

Symptom Chart - Climate Control Systems

2009 Mercury Milan Premier, 3.0 1, AWDSECTION Symptom Chart - Climate Control Systems
WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart
Symptom Chart - Climate Control Systems

Condition Possible Sources Action
  • HVAC functions verification
  • HVAC system and/or related components
  • The air inlet mode door is inoperative
  • Circuitry short/open
  • HVAC module
  • Air inlet mode door actuator/linkage
  • Incorrect/erratic direction of airflow from outlet(s)
  • Circuitry
  • Door actuator
  • Mode door binding or stuck
  • HVAC module
  • Door actuator arm not connected to the door crank
  • Insufficient, erratic or no heat
  • Low engine coolant level
  • Engine overheating
  • Plugged or partially plugged heater core
  • Temperature blend door is binding or stuck
  • Temperature blend door actuator
  • Heater hose is kinked or binding
  • The air conditioning (A/C) is inoperative
  • Fuse
  • Circuitry short/open
  • A/C system discharged/low charge
  • Dual-function pressure switch
  • PCM
  • Smart Junction Box (SJB)
  • HVAC module
  • A/C cycling switch
  • A/C compressor clutch air gap
  • A/C clutch relay
  • The air conditioning (A/C) is always on - A/C compressor does not cycle
  • Circuitry short
  • PCM
  • SJB
  • A/C compressor clutch air gap
  • A/C cycling switch
  • A/C clutch relay
  • The air conditioning (A/C) is always on - A/C mode always commanded ON
  • Circuitry short
  • PCM
  • SJB
  • Temperature control is inoperative/does not operate correctly
  • Circuitry open/shorted
  • HVAC module
  • Temperature blend door
  • Temperature blend door actuator
  • The blower motor is inoperative
  • Fuse(s)
  • Circuitry open/shorted
  • A/C blower motor switch
  • Blower motor relay
  • A/C blower motor
  • The blower motor does not operate correctly
  • Circuitry short
  • A/C blower motor resistor
  • A/C blower motor switch
  • Reduced outlet airflow
  • Circuitry short
  • A/C compressor clutch air gap
  • A/C cycling switch
  • A/C clutch relay
  • Blower motor
  • Blower motor resistor
  • Blower motor resistor
  • PCM
  • SJB
  • A/C pressure relief valve discharging
  • High system pressure
  • A/C pressure relief valve
  • CHECK the high-side system pressure. If the pressure is below the A/C pressure relief valve open pressure, REPLACE the A/C pressure relief valve. If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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