1984 300SD a/c fan speeds / operation

[300SDiesel]

I am looking for guidance on how the cc system should work. I have had all three of my cc components rebuilt by “James dean”, great guy, easy to work with.

I have two issues that I am attempting to figure out.

1. The speed of the blower seems to be low when the system is sending air through the center vents. The blower is changing speeds, just not very high, a gentle breeze is what it feels like. Should the system in Auto mode kick the fan to “high” or near to it when the interior is hot? It has been really hot and humid in Alabama this summer! If this is how the Germans designed the system, then I will live with it.

2. When the system senses the interior is reaching the temperature set on the temperature wheel, the system closes the flow to the center vents(with a clunk) and then directs the air flow to the defrost. An interesting side note, when the air is coming through the defrost, the fan speed will increase to a higher speed than when the system is using the center vents. When it is humid and cool in the morning, the windshield will fog up from the cold air the ac is putting out. Every now and then the system will switch back to the center vents.

The only system in the car not looked at is the solenoid group of 6, could that be the issue?

Thanks for the assistance, I really appreciate it.