1999 Ford Windstar, no heat, why? AC & Blower okay?

In every ford I've every owned it's a sign of low coolant. Ford used too, I don't know if they still do, mount their heater cores high in the firewall so if you were low on coolant the first sign was no heat.

If you are low find out why, leak, bad water pump, etc. My ford truck lost a little coolant through a small crack in the coolant reservoir.

Good luck

Does it have rear a/c and heat.. and the heater work there.. ?

If yes, I'd check for this instead:

Ford is known for having a thing called a blend door actuator (it determines the temperature of the outgoing air) going out on these windstars and freestars... the motor gets too weak and causes a a/c only or heat only condition usually...

real easy to change, if I remember, it's behind the radio and can be sneaked out through the radio opening (that whole center has to come out though.. radio and a/c controls)

Depends...does the fan blow? On A/C? Does the control switch from def to heat? Usually, a gear brakes in the damper control. These are motor driven these days as the old ones were vaccum controlled. The damper control motor assemblies are located behind the glove box. They cost around 30 bucks and are a dealer only item. Sorry I can't be more help, need more info. Good luck.

based on the information you have provided, I would check for a blockage in the heater lines.Or a stuck heater control valve. Low antifreeze will make the motor run hot and you wold have plenty of heat!

Possible low coolant, or it could be a vacuum leak for the heater control door. Can you switch the air to come out the heat or defrost vents or does it just come out of the dash vents?

If low coolant is not the issue it may have a pluged heater core, temperature air door maybe inop, or heater control valve maybe inop.

Check the fluids! The antifreeze may be low.

I had this on my mustang before, turned to be a broken thermostat.

Heater core or lines to it.

sounds like low antifreeze.