i have a 2000 f150 with the 5.4 liter i just bought the truck for 400 buck the heater doesnt work my blend door is working and i can see the door moving, both heater hoses are warm and ive tryed blowing threw the lines to see if the heater core is plugged up and it good and the heater core isnt leaking i havent checked the thermostat yet but thats the only thing left im stumped any help would be muchly appriciated thanks