Have you replaced the thermostat?
The headlights of a Ford Windstar may have problems going on if they are burnt out or if there is a wiring problem. Blowing a headlight fuse will also lead to both lights not working.
door contact switches grounded or bad... dave
you probably need a new blower motorCheck the fuses too -See "Related Questions" below for more
Hard starting, loss of power, poor fuel economy, and a blowing noise under full acceleration.
The horn button or relay could be stuck. The most common cause is the relay sticking closed, as opposed to the button.
bad condenser
The most common reason the heater is blows cold air on a 1999 Ford Winstar is a bad thermostat or blocked heater core.
Same problem with my 1998 Windstar. Fuel pump fuse blowing every 15 or 20 miles. Before I spent a cent on it, other then a pack of fuses, I loosened the fuel cap heard a big whoosh of air and that fixed the problem, no more blown fuses. Seemed that the vent was not working and was creating a vacuum in the tank which was overworking the fuel pump and blowing the fuse...I hope this saves a few bucks for everyone.
Compressor not running?Heater control in heat position?
verify the cables that are NOT tocuhing the metal door. Sometimes the cables are old and they crack, just put black tape (electric tape) and that should fix the problem.
you've probz already tried this, but sometime just blowing into the games slot helps
Sounds like the heater core may be plugged up or the heater damper door is broken. See "Related Questions" below for more