Pinpoint Test G: Insufficient, Erratic Or No Heat

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

G1 CHECK FOR PROPER 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?
Yes

GO to G3.

No

GO to G2.
G2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS
- Pressure test the cooling system for leaks. Refer to PRESSURE TEST ENGINE COOLING
- Does the engine cooling system leak?
Yes

REPAIR the engine coolant leak. TEST the system for normal operation.

No

GO to G3.
G3 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.
- Run the engine until it reaches normal operation temperature. Select the FLOOR position on the control assembly. Set the temperature control to full WARM.
- Feel the heater core inlet hose to see if it is hot.
  
  Fig 1: Identifying Heater Core Inlet Hose
  Courtesy of FORD MOTOR CO.
- Is the heater core inlet hose hot?
Yes

GO to G4.

No

RFFER to ENGINE COOLING to check cooling system function.
G4 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.
- Feel the heater core outlet hose to see if it is hot.
  
  Fig 2: Identifying Heater Core Outlet Hose
  Courtesy of FORD MOTOR CO.
- Is the heater core outlet hose hot?
Yes

Go To PINPOINT TEST D: DTC B1263 MODE DOOR FAILURE / INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLET(S) and diagnose for a blend door actuator.

No

INSTALL a new heater core (18476). TEST the system for normal operation.