heater control help

[cfd911]

hey guys i need help,

over the past 2 weeks i ve noticed a slight noise like a creaking under the dashboard and then yesterday my heat seems to wander from cool to hot every 10-15 seconds back and forth . all the controls work floor/ vents. i gonna assume i have a blend door that s loosing vacuum maybe a diaphram that went bad? i have a 2001 xlt 4.0 sohc regular heat/ a/c controls, any ideas????? when to start looking for a fix???? thanks joe

 

[John Frank]

I think you will find the blend door is driven by an electric motor not vacuum, vacuum is used for the flow direction to floor/def/vents the heater water control (in the engine bay) and the recurculation.
I have a 2000 Exporer limited SOHV 4.0L unless it changed on newer models.

Search for Blend Door and you shold find info about that so you can confirm or try and narrow down the fault.

 

[Dan Whitaker]

John is right. There is a servo motor (some call it an actuator) that moves the blend door.

 

[shamaal]

Picture may be of help. I no longer remember which Explorer family this is from, but yes the blend motors are electric on the later models.