the floor pan could be sagging due to rot around the heater channel. common cause.
coolant level could be low not letting it circulate through the heater core, causing it to blow cold. Also, if the coolant level is low it will in turn overheat.
Could be a bad thermostat or heater core
Could be a Faulty relay.
it could be a couple of things you could have a bad thermostat or a bad heater core
Your heater coil is bad.
there is a short somewhere in dash or heater, you need to fix that to stop fuses blowing
If the fan is not blowing, a fuse may be the cause. If there is just not warm air being blown by the fan, check your coolant level in your radiator. Low level of water and coolant will cause the heater to blow cooler air.
well you could just turn the heater off heater blower ---- If it is a car heater then check your coolant level. the heater is driven off a heat converter that is fed by the radiator system. When the coolant fails to pump round the radiator system the car internal heater doesn't work. Driving without coolant in the system will result in the engine overheating and seizing.
could be head gasket problem. does your heater work? might need heater core , clogged up. do compression test. or bypass heater core and see if that works.
It could be a thermocoupler, happened to my furnace in middle of night a few years ago.
the heater box is under the dashboard most of the time in the middle. The heater blowing system have doors . The door for the foot is next to your leg he have one metal cable could be this come out. If yes, have to clip it back. This electric its more difficult but just check first
heater core could be rusty and old or line to heater core could be plogged most likely old heater core
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.
If it's blowing and you can tell the compressor is still kicking on when you turn the A/C on, the Coolant probably just needs to be recharged. Especially in a 9 year old car.
Thermostat stuck open, clogged heater core, heater flow valve not functioning, or low of coolant.
It could be the heater valve which is located under the hood to the passenger side down below the radiator and fan units.
You could have a vacuum leak, a bad controller, a bad air door or an electrical problem.......
Is it a fish smell or a rotten egg smell ? FISH SMELL COULD BE A BAD HEATER CORE, THIS WOULD CAUSE YOU NOT TO HAVE HEAT IN THE CAR , BUT IT MIGHT NOT CAUSE CHECK ENGINE LIGHT TO COME ON UNLESS MAYBE CAR IS LOW ON COOLANT. ( THERE MIGHT BE A LOW COOLANT SENSOR TO TRIGGER CHECK ENGINE LIGHT) ROTTEN EGG SMELL COULD BE A CLOGGED CATALYTIC CONVERTER , WHICH WOULD CAUSE THE OXYGEN SENSOR TO TRIGGER THE CHECK ENGINE LIGHT, BUT IT WOULDN'T CAUSE THE LOSS OF HEAT.
Depends. You might be low on coolant. Or your heater core could be clogged. Neither of those instances is particularly "safe". But, it could just be a blend door, which wouldn't matter.
Could be, low on coolant, stuck open thermostat, plugged heater core, temp blend door malfunction,
Blocked heater core, faulty heater valve, disconnected connection to the heater valve.
you can tell if your heater cooling system/core is broke as the car will not produce heat when you turn on the heat inside the car. if it is not blowing heat there could there is a problem. the heater core itself should look like a small radiater, if that is clogged it could cause a problem. can also possibly fix this by doing a cooling system flush this will clear any blockages or expose the problem. if flush works, consider the thermostat. that also will cause no heat on inside.
Could be, Low on coolant, A stuck open thermostat, A plugged heater core, A faulty temp blend door actuator,
It could be steam from the heater core