Vent System Conundrum

[h82crash]

I have a new-to-me 95 M3. I also have a 93 325is. Both have the same knob control panel.

In the 325, when I turn the knurled wheel to red, it makes the air in the vents warm...that's all. In the M3, when I turn the wheel to red, the air goes warm, but also the flow to the center dash vent is cut like 90%.

I read the owners manual for the M3 and apparently that is the intended way it functions. Did it change from 93 to 95?

Also, other issues with the M3.
1) The air flow at the foot well vents is almost non existent when set to foot well, or any other setting on the dial.

2) Air always flows out the defroster vents, except for one little position on the dial, like 2 clicks down from the foot well setting. Flap issues? Control knob issues?

3) I am wondering if I can get the M3 to function like the 325, which would be preferred.

I guess I'm looking at tearing into the dash to address these issues.

Can others tell me how their red/blue knurled wheel affects their vent operation?

[shogun]

Copy moved to E36 M3 forum

[h82crash]

So, no one has a red/blue wheel that works or wants to tell me how it works in their car?

For general info, does your knurled wheel just change temperature, or does it also interrupt airflow out the center vent?

Also, anyone with experience in the operation of the diverters or repairs?

[MParallel]

I have explained this so many times,
might as well do it again. Although owner’s manual explains it.

The knurled wheel controls the stratified air flap inside the heater core and affects the face vents only. It works as
as a main temp override. Idea is you can have set it too full hot, but get cooler/cold air from the face vents.

When set to full cold, incoming air is passed straight through the vents, as this bypasses the heater matrix.
That’s why airflow feels so much more, as there is no restriction.