1979 116 climate control fiasco/help

[DaveMcDonald]

I have a 1979 300SD. Its a sweet car, and I am preparing to sell it. It only has 130K original miles. Anyway, I cant seem to get the climate control sysyem to function properly. First, heres whats been replaced: servo (rebuilt/ stainless, 5 button push buttons, amplifier checks good). the air conditioning has been retrofitted and works excellent, however the a/c will not turn off at the switch, only if I turn off the blower. THE SWITCH is GOOD. I have taken it apart and cleaned it, its just like the power window switch, and I'm familiar with the symptoms of corroded switches. I dont know why it wont shut off at the switch, there is no indication of anyone attempting to straight wire to bypass a defective amplifier. Also, having mentioned replacing the 5 button switch, the defrost and bi-level dont work at all, and high blow only works, low blow setting blows high.This is the most absurd climate control design I have ever messed with. Anyone have any insight on where I might start to rectify this climate control fiasco??? Thanks Dave (407) 716-6212...by the way the car is for sale 3500...new windshield, new front/rear window gaskets, new rear bilsteins, euro headlights, no rust whatsoever, excellent interior, perfect dash, new hirchmann aftermarket antenna, kenwood cd player,new tumbler with key,nice car, climate control funky.