I have a 2005 taurus. the heat blows out of the floor vents great but there is no heat coming from the dashboard and doesn't defrost, what could be the problem?

bad vac lines,is vac controlled,or the control unit is bad.

Thanks for your help, from what I have been told to make it clear to me now is no matter where the temp selector is set to the heat or cold only blows from the floor vents, not the dashboard vents

to continue, it's not a problem with the fan control, selector, it is within the vent, floor, defrost selector that only blows from the floor vents and no where else

like said above,vacume leak,under hood on driver side next to master cylender you will see a round plastic valve with vac lines ,1 going in 1 out,check from one going in back will see 3 lines hooked to a T check for cracks where they hook,feel for softness in vac lines,also the valve mentioned could be bad,can get it at any parts store in help section around $4.00.the vent door that changes it from floor to vent to defrost is vac controlled.

when you speak of bad vac valve or control unit. is it referred to as an egr or something else? Thanks for all the info. it's greatly appreciated.

im talking about the round plastic valve that the rubber vacume lines hook to at firewall on drivers side under hood near the brake booster,control panell unit is where you turn the heat on,on dash,the EGR has nothing to do with the heat,it helps engine idle.