I have a 1992 Toyota Camry. When I turn on the heater the blower works well but the air is barely luke warm. When I change the setting to recirculate the air, the air blows nice and hot. Change the slider back to outside air and it gets cold again.
I thought cabin filter but apparantly the 92 model doesn't have one. When I change between floor, dash vents, and defrost the air is correctly re-directed.