Pinpoint Test K : Insufficient, Erratic Or No Heat: Notes
WARNING: This page is about a different car, the 2015 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic Overview
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Diagnostic Methods in Service Information for information about these practices.
Normal Operation and Fault Conditions
Warm coolant flows from the engine through the heater core and back to the engine. Proper coolant temperatures are critical for good heater performance.
Possible Sources
- Plugged or partially plugged heater core
- Low engine coolant level
- Temperature blend door actuator(s)
- Temperature blend door(s) binding or stuck