I always thought the heater controls on the Series ll dash were confusing. When I first got my car in Houston I had the opposite problem and wanted to turn off all the heat possible but did not have them set right for the first few months. Pay attention to the HOT COLD ON OFF arrows for the air and heat for what you want and as Josh says play around with the round chrome knobs on each side of the dash with the fan high to get an idea how they direct the flow to the floor or defrost vents.. You might also check that the LH lever for AIR does open and close the spring loaded flapper door on the bottom of the heater box. My door will hang up some times. On my car I can hear the door slam open and closed when I work that lever and nothing is hanging up
David Barnes
68 E-Type FHC