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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1006 (Climate Control System - General Information And Diagnostics - F250-F550) >> Diagnostic Tests >> Climate Control System >> Pinpoint Tests >> Pinpoint Test H: Insufficient, Erratic Or No Heat >> Pinpoint Test H: Insufficient, Erratic Or No Heat

Pinpoint Test H: Insufficient, Erratic Or No Heat

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. H1 CHECK FOR CORRECT ENGINE COOLANT LEVEL 
    • Key in OFF position.
    • Check the engine coolant level when hot and cold.
    • Is the engine coolant at the correct level (hot/cold) as indicated on the engine coolant recovery reservoir? 
    1. YES  : Go to  H3.
    2. NO  : Go to  H2.
  2. H2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS 
    • Pressure test the cooling system for leaks. Refer to ENGINE COOLING article.
    • Does the engine cooling system leak? 
    1. YES  : REPAIR the engine coolant leak. TEST the system for normal operation.
    2. NO  : Go to  H3.
  3. H3 CHECK FOR COOLANT FLOW TO THE HEATER CORE 
    WARNING: The heater core inlet hose will become too hot to handle and may cause serious burns if the system is working correctly.
    • Key in ON position.
    • Run the engine until it reaches normal operation temperature. Select the FLOOR position on the control assembly. Set the temperature control to full WARM.
      • Fig 1: Checking Coolant Flow To Heater Core
      GF0001297Courtesy of FORD MOTOR CO.
    • Feel the heater core inlet hose to see if it is hot.
    • Is the heater core inlet hose hot? 
    1. YES  : Go to  H7.
    2. NO  : Go to  H4.
  4. H4 CHECK FOR COOLANT FLOW TO THE HEATER CONTROL VALVE 
    WARNING: The heater control valve inlet hose will become too hot to handle and may cause serious burns if the system is working correctly.
      Fig 2: Checking Coolant Flow To Heater Control Valve
      GF0007927Courtesy of FORD MOTOR CO.
    • Feel the heater control valve inlet hose to see if it is hot.
    • Is the heater control valve inlet hose hot? 
    1. YES  : Go to  H5.
    2. NO  : REFER to ENGINE COOLING article.
  5. H5 CHECK FOR VACUUM AT THE HEATER CONTROL VALVE 
    NOTE: Vacuum should not be present in FLOOR and full WARM. Vacuum should only be present in MAX A/C.
      Fig 3: Checking Heater Control Valve Vacuum Connector For Vacuum
      GF0007928Courtesy of FORD MOTOR CO.
    • Disconnect the heater control valve vacuum connector and check for vacuum.
    • Is vacuum present at the heater control valve? 
    1. YES  : Go to  H6.
    2. NO  : INSTALL a new heater control valve. TEST the system for normal operation.
  6. H6 CHECK FOR INCORRECT VACUUM LINE PLACEMENT 
    • Key in OFF position.
    • Inspect the heater control valve and A/C vacuum lines for correct placement.
    • Is the vacuum line placement correct? 
    1. YES  : Vehicles with manual climate control, INSTALL a new climate control assembly. TEST the system for normal operation.

      Vehicles with EATC, go to  H8 .

    2. NO  : CORRECT the vacuum line placement. TEST the system for normal operation.
  7. H7 CHECK FOR A PLUGGED OR RESTRICTED HEATER CORE 
    WARNING: The heater core outlet hose will become too hot to handle and may cause serious burns if the system is operating correctly.
      Fig 4: Check Plugged Or Restricted Heater Core
      GF0001298Courtesy of FORD MOTOR CO.
    • Feel the heater core outlet hose to see if it is hot.
    • Is the heater core outlet hose hot? 
    1. YES  : Vehicles with manual climate control, go to Pinpoint Test K .
    2. Vehicles with EATC, go to Pinpoint Test A .
    3. NO  : INSTALL a new heater core. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
  8. H8 CHECK THE CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: EATC Module C228a
    • Disconnect: RSA Module C2093
      • Fig 5: Checking Circuit For Open
      GF0007929Courtesy of FORD MOTOR CO.
    • Measure the resistance between the EATC module C228a-11, circuit 1111 (VT) and the RSA module C2093-6, circuit 1111 (VT).
    • Is the resistance less than 5 ohms? 
    1. YES  : INSTALL a new RSA module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
    2. NO  : REPAIR circuit 1111 (VT) for an open. TEST the system for normal operation.
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