Would like to change my own cabin filter, but I do not know where it is.
 Is there a service manual for the 2001 ford Windstar? I have a clicking
 sound .like a vent door trying to open or close when the heater is on. To
 get the heater to blow warm air. I usually have to have all the back vents
 on. The same with the air conditioner. It also has a clicking noise. Is
 this something I can fix?   Thank you for your time and help.

Robert

That clicking is probably related to some jammed doors in the plenum - the
actuators make that noise when they try to move the door and it won't move.
A tech would remove the actuators and try to move the doors by hand - if
they move freely, the actuator(s) would be replaced.  If not, the plenum has
to come out for repairs.

Here's the cabin air filter location: (see attachment)

Hope this helps...

Richard

Richard, you where right on with your diagnosis of the heating problem. The repair is done and the heater is working. thank you...

Robert