most likely a bad heater core or the little gate type valve that changes from heat to air and back. or it could even be the switch.
most of the windstars have two heater cores not just one.
at least this is a place to start.
This "flap" is the temperature blend door which directs air over & through the heater core.The "Related Questions" below are intended to help explain some of the basics of Windstar heating/cooling functions and terminology.That should help in the investigation of the specific problem on the vehicle, and ultimately leading to a fix.Start with the "Where is the heater control valve located on a Ford Windstar" question and then move on to the "What could cause a Windstar to have no heat - or not be able to adjust the temperature"
Could be the temperature sending unit.See "Related Questions" below for more specifics...
Could be the PCV valve is faulty.. Checking mine tomorrow for the same reason!
A serious vacuum leak could cause that.
temperature
A blocked heater hose could cause a leak. A stopped up heater core could as well. Or the connector in the Windstar could be cracked.
Try this solution. http://www.leckemby.net/windstar/windstar01.html It seems that Windstars have a problem with the intake manifold.
It depends on how low a temperature and what other symptoms they have. Hypothermia could be one cause
Of steam seal on a steam turbine temperature in incorrect could cause damage. This could cause it not to work right.
lower it below or raise it above the the optimum temperature
temperature sensor, fan relay, or fans themselves are bad.
my 2001 ford windstar is still overheating even though i changed out the thermostat. what could it be?