1988 E150 front only heat/air
Yes it would normally blow hot air with the compressor unplugged if it were hot outside.

Last year I rebuilt my AC system and it just didn't cool as well as I thought it should. The temps out the vents would get near 40F till the engine warmed up and then it was around 55 to 60F.
Last week it was about 55F outside and I thought I would unplug the compressor and put the hvac selector on max ac with the temperature selector in the cool position and see what happened. It was blowing out hot air just the same as if it were in heat mode. I also tried it on normal ac, same thing.
The fresh air vent is opening and closing. The Defrost to heat is also swapping.

The best I can tell from my manuals is that the temperature control selector must use a cable to go to a Temperature Control Door. My manual does not show a cable or vacuum motor.
RA lists a heater hose valve.
My EVTM shows a heater valve mounted in one of the heater lines outside under the hood but my manual does not and there is not one on the van. The heater hoses look stock.

Any ideas?
When I move the temperature control level it does feel like it has some pressure on it but it feels even all the way across as you slide it.

I see nothing in the diagrams showing a cable. I am guessing it would connect to the Evaporator Temperature Control Door Lever which I think works the Air Inlet Temperature Control Door. If so, how do you get access to it?



Here is a simpler view


Here is the heater hose routing with no valve shown.