What's the best source for a replacement heater control valve? I expect the one in my 82 242 is original - and it doesn't seem to want to shut off. I've got heat to the core all the time - no matter where the control lever is set to. And the cable is actuating the valve properly - it's physically rotating the valve lever all the way to closed. I've got to do a blower motor replacement, and figure I might as well fix this while I'm there.