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Home >> Mercury >> 2010 >> Milan Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1200 (HVAC - Climate Control System - General Information And Diagnostics - (Hybrid)) >> Diagnosis And Testing >> Climate Control System >> Pinpoint Tests >> Pinpoint Test N: Insufficient, Erratic or No Heat >> Pinpoint Test N: Insufficient, Erratic Or No Heat

Pinpoint Test N: Insufficient, Erratic Or No Heat

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
  1. N1 CHECK FOR CORRECT ENGINE COOLANT LEVEL 
    • Ignition OFF.
    • 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? 
    • Yes:  GO to  N3.
    • No:  GO to N2  .
  2. N2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS 
    • Pressure test the cooling system for leaks. Refer to PRESSURE TEST .
    • Does the engine cooling system leak? 
    • Yes:  REPAIR the engine coolant leak. TEST the system for normal operation.
    • No:  FILL and BLEED the cooling system. REFER to COOLING SYSTEM DRAINING, FILLING AND BLEEDING . After filling and bleeding the cooling system, GO to N3  .
  3. N3 CHECK FOR COOLANT FLOW TO THE HEATER CORE 
    • Start the engine and let the engine idle until it shuts down automatically,
    • Select FLOOR mode.
    • Set the temperature to the warmest setting.
    • Select the lowest blower motor setting.
    • Using a suitable temperature measuring device, check the heater core inlet hose to see if it is hot.
    • Is the heater core inlet hose hot? 
    • Yes:  GO to N4  .
    • No:  GO to  N5.
  4. N4 CHECK FOR A PLUGGED OR RESTRICTED HEATER CORE 
    • Using a suitable temperature measuring device, measure the heater core outlet hose temperature.
    • Is the heater core outlet hose temperature similar to the inlet hose temperature (within approximately 6-17°C [10-30°F])? 
  5. N5 CHECK FOR COOLANT FLOW TO THE AUXILIARY COOLANT FLOW PUMP 
    • Using a suitable temperature measuring device, check the auxiliary coolant flow pump inlet hose to see if it is hot.
    • Is the auxiliary coolant flow pump inlet hose hot? 
  6. N6 CHECK CIRCUIT CB107 (GN/BU) FOR VOLTAGE 
    • Ignition OFF.
    • Disconnect: Auxiliary Coolant Flow Pump C1560.
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: DataLogger - PCM  .
    • Toggle the Heater Pump Commanded (HPUMP) output command ON.
    • Measure the voltage between auxiliary coolant flow pump C1560-2, circuit CB107 (GN/BU), harness side and ground.
      Fig 1: Checking Circuit CB107 (GN/BU) For Voltage
      G06262723Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  GO to N7  .
    • No:  CARRY OUT the auxiliary coolant flow pump relay component test.

      Refer to appropriate SYSTEM WIRING DIAGRAMS article for component testing.

      If the relay tests OK, GO to  N8.

  7. N7 CHECK CIRCUIT GD120 (BK/GN) FOR GROUND 
    • Ignition OFF.
    • Measure the voltage between auxiliary coolant flow pump C1560-1, circuit GD120 (BK/GN), harness side and auxiliary coolant flow pump C1560-2, circuit CB107 (GN/BU), harness side.
      Fig 2: Checking Circuit GD120 (BK/GN) For Ground
      G06262724Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  INSTALL a new auxiliary coolant flow pump. REFER to AUXILIARY COOLANT FLOW PUMP . TEST the system for normal operation.
    • No:  REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
  8. N8 CHECK THE AUXILIARY COOLANT FLOW PUMP RELAY VOLTAGE SUPPLY 
    • Ignition OFF.
    • Disconnect: Auxiliary Coolant Flow Pump Relay  .
    • Ignition ON.
    • Measure the voltage between ground and auxiliary coolant flow pump relay socket, circuit SBB14 (BN/RD).
      Fig 3: Measuring Voltage Between Ground And Auxiliary Coolant Flow Pump Relay Socket Circuit SBB14 (BN/RD)
      G06394472Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  REPAIR circuit CB107 (GN/BU) for an open. TEST the system for normal operation.
    • No:  VERIFY Battery Junction Box (BJB) fuse 14 (10A) is OK. If OK, REPAIR circuit SBB14 (BN/RD) for an open. TEST the system for normal operation. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
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