I have a new to me 1976 '02. With no fan or heat on, as soon as my car warms up I have heat blasting on my feet and my passenger's feet. I mean really really hot. My car is not overheating. If I switch the defrost on, I get a nice blast on my face and a lesser blast on my feet. I have no coolant leaks interior or exterior. All switches are off or in the coolest position possible. The air is not working and all of those switches are also off. I have already replaced the water pump and thermostat due to a leaky water pump. Any suggestions for what to try or investigate? I will probably love this problem in the winter, but not so much when it is 90+.
My recollection is that the 2002's heater valve is a cable-operated mechanical one in the middle of the cowl. If the cable to it is broken or loose, it's stuck in one position. As a temporary fix, you can manually set it. It's on the lower left in this picture:
