Four Seasons 70021 HVAC Heater Core Temperature Sensor

HVAC Heater Core Temperature Sensor for Ford, Lincoln, and Mercury

Four Seasons 70021 is an HVAC heater core temperature sensor built for vehicles equipped with automatic temperature control systems. It uses a female connector with 2 terminals and an alternate connector design, making it a direct-fit temperature unit for select Ford, Lincoln, and Mercury applications.

Key Features

• Four Seasons Temperature Unit line for HVAC temperature sensing applications
• Female connector with 2 terminals
• Connector shape: other design
• Direct replacement for HVAC heater core temperature sensor service
• Part number 70021 for easy identification and ordering

Detailed Description

This Four Seasons 70021 HVAC heater core temperature sensor monitors temperature input within the heating and air conditioning system so the control module can manage cabin temperature accurately. It is listed for 2006-2009 Ford Fusion, 2007-2009 Lincoln MKZ with HVAC systems featuring Automatic Temperature Control (ATC), and 2006-2009 Mercury Milan. The Four Seasons Temperature Unit line focuses on HVAC sensing components used in climate control service, and this sensor follows that application-specific design.

This part cross-references Dayco 70021 for the same application. The Four Seasons 70021 part number is also referenced under OE-style numbers used in related HVAC service catalogs.

What It Helps Address

• Incorrect cabin temperature readings from the HVAC system
• Automatic Temperature Control (ATC) sensor faults on Lincoln MKZ applications
• Heating or cooling output that does not respond correctly to temperature input
• HVAC diagnostic trouble codes tied to heater core temperature sensing
• Intermittent climate control performance in Ford Fusion and Mercury Milan models

Installation Notes and Tips

Verify connector style, terminal count, and vehicle fitment before installation. Confirm the application matches your Ford Fusion, Lincoln MKZ, or Mercury Milan by model year and HVAC configuration, especially on MKZ vehicles with ATC. Inspect the connector and wiring for corrosion or damage before replacing the sensor, and clear HVAC fault codes after service if required by the vehicle.

Quality Assurance

Four Seasons supplies HVAC service parts for temperature control applications, and this sensor is cataloged for direct vehicle-specific fitment. Part number 70021 is listed for 2006-2009 Ford Fusion, 2007-2009 Lincoln MKZ, and 2006-2009 Mercury Milan.