There's the heater core itself - getting plugged up
And then there's the blend door itself - they've been know to get stuck and/or break.
See "Related Questions" below for more
If by "heater box" you're referring to the heater core, we've got you covered with the "Related Questions" below.Be sure to review the questions regarding the blend door and blend door actuator motor - other very popular heating/cooling parts in the Windstar
Before replacing the thermostat or any other component of the Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair.
Before replacing the thermostat, it is worth checking to see if the blend door is broken or the blend door actuator is failing. The most common issue relating to thermostat and climate control in Ford Windstar vans is the blend door. CHECK TO SEE IF IT IS BROKEN BEFORE REPLACING OTHER COMPONENTS (i.e. Thermostat, heater core, etc.). The Blend Door actuator on the Ford Windstar can be found by removing the glovebox. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair. Linked here is a video from www.heatertreater.net demonstrating how to access components of the plenum box for repair without disassembling the entire dash.
Before replacing the thermostat or any other component of the Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair. Linked here is a video from www.heatertreater.net demonstrating how to access components of the plenum box for repair without disassembling the entire dash. http://www.heatertreater.net/Windstar%20Video.html This details the best DIY option on how to replace a broken blend door or actuator, accessing the plenum box by removing the glove box rather than the entire dash.
Before replacing the thermostat or any other component of your Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair.
Before replacing the thermostat or any other component of the Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair. Linked here is a video from www.heatertreater.net demonstrating how to access components of the plenum box for repair without disassembling the entire dash. http://www.heatertreater.net/Windstar%20Video.html This details the best DIY option on how to replace a broken blend door or actuator, accessing the plenum box by removing the glove box rather than the entire dash.
Assuming we are talking about the temp blend door actuator, if the air coming out of the heater ducts in the cab is cold and the temperature control is on hot and the engine is running and fully warmed up (195 degrees) and the coolant reservoir is on the full mark and both heater hoses under the hood are hot, you probably have a faulty temp blend door actuator. If you have one heater hose that is hot and the other is only warm or cold, you probably have a plugged heater core. If both heater hoses are only warm or cold you probably have a stuck open thermostat.
With vehicle warmed up and running feel both heater hoses with your hands. If one hose is hot and the other is cold or luke warm, the heater core is plugged. Flushing the heater core should help. If both heater hoses are hot, the temp blend door actuator behind the dash may be broken in which case the entire dash assembly would have to be removed to repair/replace the temp blend door actuator.
It sounds like the problem is a broken blend door. Before replacing the thermostat or any other component of the Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair.
Assuming the coolant level is full, it could be a stuck open thermostat or a plugged up heater core or the temp blend door actuator is broken. Run the engine for 10 minutes or more then feel with your hands both heater hoses, if they are both only luke warm change the thermostat. If one is hot and the other is luke warm flush the heater core. If they are both hot I would suspect the temp blend door actuator isn't working.
Before replacing the thermostat or any other component of the Windstar's HVAC system, be sure to check your blend door for functionality FIRST. The most common issue with heat or A/C in the late model Ford windstar is a broken blend door. A broken blend door actuator is almost as common as a broken blend door itself. Typically, the fix requires disassembling the entire dash and replacing the whole plenum box, which can be a costly repair. demonstrating how to access components of the plenum box for repair without disassembling the entire dash.
What about the blend door itself? They are known to break loose from the shaft they mount to. Also, with the engine running and fully warmed up, feel both heater hoses as they enter the heater core from under the hood, they should both be quite hot (180+ degrees F). If one is hot/warm and the other is warm/cold, the heater core may be blocked/plugged. If that is the case give the heater core a good flush with the garden hose. If both heater hoses are hot, you still have a blend door problem as stated above. If both heater hoses are cold, you may have a stuck open thermostat or you are very low on coolant. See "Related Questions" below for more