Pinpoint Test L: Insufficient, Erratic Or No Heat
WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
- L1 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?
- L2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS
- Pressure test the cooling system for leaks. Refer to COOLING SYSTEM PRESSURE TEST or COOLING SYSTEM PRESSURE TEST .
- Does the engine cooling system leak?
- Yes: REPAIR the engine coolant leak. TEST the system for normal operation.
- No: GO to L3.
- L3 CHECK FOR COOLANT FLOW TO THE HEATER CORE
- Run the engine until it reaches normal operation temperature. Select the FLOOR position on the control assembly. Set the temperature control to full warm and the blower to the lowest 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 L4.
- No: REFER to ENGINE COOLING or ENGINE COOLING to check cooling system function.
- L4 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])?
- Yes: For EMTC systems, Go To PINPOINT TEST P and diagnose for a temperature blend door actuator. For DATC systems, Go To PINPOINT TEST Q and diagnose for a temperature blend door actuator.
- No: INSTALL a new heater core. TEST the system for normal operation.