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Climate Control Pinpoint Test 2: Insufficient, Erratic Or No Heat

CLIMATE CONTROL PINPOINT TEST 2 CHART - INSUFFICIENT, ERRATIC OR NO HEAT

PINPOINT TEST 2 INSUFFICIENT, ERRATIC OR NO HEAT
STEP INSPECTION ACTION
1 INSPECT FOR CORRECT ENGINE COOLANT LEVEL
  • Key OFF.
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  • Inspect the engine coolant level when the engine is hot and when cold.
  • Is the engine coolant at the correct levels? 
 Yes Go to step 3.
No Go to next step.
2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS
WARNING:
  • Never remove the radiator cap under any conditions while the engine is operating. Failure to follow these instructions could result in damage to the cooling system or engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the radiator, use extreme care when removing the radiator cap from a hot radiator. Wait until the engine has cooled, then wrap a thick cloth around the radiator cap and turn it slowly to the first stop. Step back while the pressure is released from the cooling system. When it is certain all the pressure has been released, press down on the cap (still with a cloth), turn and remove.
  • Fill the engine cooling system to the specified level.
  • Pressure check the cooling system, including the radiator cap. See RADIATOR PRESSURE TEST INSPECTION - 2.3L for the 2.3L engine, or see RADIATOR PRESSURE TEST INSPECTION - 4.0L for the 4.0L engine to check the engine cooling system function. It is not necessary to check the components separately at this time.
  • Does the engine cooling system, including the radiator cap, hold pressure? 
 Yes Go to next step.
No Repair the engine cooling system leak. Test the system for normal operation.
3 CHECK FOR HOT COOLANT AT THE HEATER CORE INLET HOSE
WARNING:
  • The heater core inlet hose will become too hot to handle and can cause serious burns if the system is working correctly. Failure to follow these instructions may result in personal injury.
  • Key ON engine running (KOER).
  • Allow the engine to reach normal operating temperature.
  • Place the function selector switch in the floor position and the temperature control switch in the full warm position.
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  • Feel the heater core inlet hose.
  • Is the heater core Inlet hose too hot to handle? 
 Yes Go to next step.
No Go to step 5.
4 CHECK FOR HOT COOLANT AT THE HEATER CORE OUTLET HOSE
WARNING:
  • The heater core outlet hose will become too hot to handle and can cause serious burns if the system is working correctly. Failure to follow these instructions may result in personal injury.
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  • Feel the heater core outlet hose.
  • Is the heater core outlet hose too hot to handle?
 Yes See CLIMATE CONTROL PINPOINT TEST 6: NO OPERATION IN ALL TEMPERATURE SETTINGS  .
No Carry out the heater core component test. See HEATER CORE INSPECTION to determine whether a plugged or partially plugged condition exists.
5 CHECK FOR HOT COOLANT AT THE HEATER CONTROL VALVE INLET HOSE
WARNING:
  • The heater control valve inlet hose will become too hot to handle and can cause serious burns if the system is working correctly. Failure to follow these instructions may result in personal injury.
  • Key OFF.
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  • Feel the heater control valve inlet hose.
  • Is the heater control valve inlet hose too hot to handle? 
 Yes Go to next step.
No See COOLING SYSTEM INSPECTION - 2.3L for the 2.3L engine, or see COOLING SYSTEM INSPECTION - 4.0L for 4.0L engine to check the engine cooling system function.
6 CHECK FOR VACUUM TO THE HEATER CONTROL VALVE
WARNING:
  • When disconnecting the heater control valve, position the vacuum line away from the cooling fan and the accessory drive system. Failure to follow these instructions may result in personal injury.
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  • Disconnect the vacuum line from the heater control valve.
  • Key ON engine running (KOER).
  • Check for the presence of vacuum at the heater control valve vacuum line.
  • Is vacuum present?
 Yes Install a new heater control valve. Test the system for normal operation.
No Go to next step.
7 CHECK FOR INCORRECT VACUUM LINE PLACEMENT
  • Key OFF.
  • Inspect the heater control valve and A/C vacuum lines for correct placement.
  • Is the vacuum line placement correct? 
 Yes Install a new climate control assembly. See HEATER CONTROL UNIT REMOVAL / INSTALLATION . Test the system for normal operation.
No Correct the vacuum line placement. Test the system for normal operation.
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