Can't take the heat
 

My 83' 944 puts out constant heat even when the temp lever is on full cold. I just had the temp control panel (and clips) replaced. The mechanic also replaced a hose on the Y fitting. All wires appear to be connected (valve moves when lever moves), yet I still have HEAT! Could it be the heater control valve? Can it be tested in car? It looks like a real pain($$$) to remove.

I would try the heater valve. Mine was leaking. You can test it by having someone sit in the car and turn the hot/cold switch back and forth while you watch the valve in the engine compartment. With the ignition on of course. The lever should go back and forth. If it doesn't replace it. Good luck.