As fall approaches I notice my heater is not putting out warm air. The temp guage shows that the water temp is warming up proberly. The blower works and the AC works great. The selector moves the air between vents and defroster just fine. The floor vent doesn't work, but whose does anymore? The car is a '97 Mark VIII with 120K miles. Is this something that normally goes out about this time? Is it something I can fix? I know which end of a screwdriver is the important one and I have worked on other cars, but I am currently living in a house with no carport nor garage. So, any job has to be one that can be wrapped up easily.