Heater blows hot all of the time.

THE HEATER CONTROL CABLE, VALVE, OR SOLENOID IS STUCK OPEN......LETTING COOLANT INTO HEATER CORE AT ALL TIMES
FIND BAD COMPONENT-REPAIR

if your heater fan blows all the time when you turn the switch on, then check the heater control valve under the hood right before the heater core. its inline with your heater hoses going into the heater core. the valve opens one way and closes the other way as you turn the switch from hot to cold.

Heat control switch is bad if you turn it all the way cold and it still blows hot air.

you have a leak in the vaccum line,or the heater control switch is suck.

The next possibility, if you haven't already thiught of it, is as simple as making sure there is enough water/antifreeze solution in your radiator. If the level is too low, your hoses will get hot, but there will not be enought water to circulate into your heater core.

there should be a temperature door, but I don't know if there is a cable or if its electric. turn the temp knob, if it feels like it moves anything? I dont have a diagram here at home, but will monday/

Yes clogged heater core may be the answer in your case .

Taurus does not use a heater control valve. It runs coolant thru the heater core constantly. You may have a temp blend door actuator problem or a plugged up heater core is also very common. Feel the heater hoses, they should both be very hot, it one is much cooler; you can try to back flush the core.

The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.

To attempt to clean the core, you must flush the system multiple times. If this does not work, the core cannot be cleaned and must be replaced.

The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.

if the car is not overheating, the thermostat is working fine.... replace or flush the heater core multiple times to try and eliminate sediment build-up.