heat does not work.gage on dash is normal.fluid in rad. is right on. on 2003 Ford Windstar

i have no heat.the gage on the dash is normal.the a/c works fine.sometimes there is a flapping noise under the dash.

Asked by for the 2003 Ford Windstar
It sounds like you may have a blend door problem. Have the climate control system computer scanned to see if the position of the blend door is changing properly.