Podguy

That is because 78 and 79 does not have climate control. 80 on up supposedly you could set an interior temp and the system would maintain it switching from cool to warm air automatically, although I think on the early models if the A/C was on it just stayed on and got blocked.

Alan

On all models equipped with AC - when selected the AC stays on all the time unless the Evap freeze switch activates - it never cycles for temperature control.

I thought this odd when I figured it out - but its typical on most cars - just easier to manage that way.

Very wasteful if you leave the AC on when not needed though (e.g outside ambient is below the temp you want to set).

Alan

SteveG

"stays on all the time . . . " I'm missing something here. What is does the temp slider do then? How does the temp slider affect cabin cooling?

Ad0911

My best guess is that it allows warm water to pass through the heater. So you effetively heat upmthe cold air. Happily all this heat doesn't cost extra fuel.

Aloysius

I think the heater control swings a flap in the air distribution box (heater contol flap) between the cool/outside ambient air (for those without ac) and the heated air. On the automated temp control the program swings the flap to adjust the temp, constantly, to achieve the desired mix and resulting mix. I think this is how it works. There must be some point in the temp control that closes the heater valve when you want cold air below a certain temp.