That is the mix door actuator trying to move the door, it may be stuck or you might have a vacuum leak coming from the engine. The actuator may be bad as well.
Replace fuse #36 in the inside fusebox.See "Related Questions" below for more
there is a bit of rubish caught in the heater fan.
The blower on the back heater may need to be replaced on the 2000 Ford Winstar.
my 1999 winstar was doing this and it was the blend door
have found that a ticking noise on the passenger side (under the dash) in the heater b5pdox (you can feel the vibration) on a 1997 town car is probably a vaccumn control switch.
The most common reason the heater is blows cold air on a 1999 Ford Winstar is a bad thermostat or blocked heater core.
It does not have a heater control valve.It does not have a heater control valve.
The "Related Question" below is an extensive discussion on the 1999-2003 temperature control valve / heater control valve. It is likely the information will be similar to the 1997 / 1998 Windstar
The ticking could be just the pipes expanding and contracting. Or, the heating elements could have a build up that occurs over time.
most likely a faulty relay
The Taurus does not have a heater control valve. Coolant flows through the core at all times. Be sure to review the "Related Question" below for much more about Taurus temperature controls
Where is the the heater control valve??