hi everybody
I am working on a 97 exporer with the 5.0
If you manualy manipulate the heater control valve the air tempeture will change, but the valve will not move when using the switch.

I checked for vacume at the valve and there is a constant vacume regardless of switch position.

where do i look next, what controls the vacume that controls the heater control valve?

Thanks for the help guys.

 

Does your Explorer have the manual (****) HVAC controls or electronic climate controls? I don't recall if both use a vacuum controlled heater control valve. The valve is controlled by the climate control control unit via vacuum lines and a vacuum reservoir. I'm struggling to find the vacuum diagram currently in the service manual to determine if vacuum opens or closes the valve.

-Rod

 

I though the valve closed when you go to MAX AC... all other positions it is open.