Heater blow's cool air on 2007 Ford Explorer Sport Trac

tell me what to check

make sure the coolant level is correct. the thermostat needs to be checked as the water needs to be hot. check the heater hoses. they must be hot as well, one hot and one cold says the heater core may be clogged. and lastly, the blend door motor which is a common failure may be at fault.

Thank You,