Thanks Dave,
The main fan is doing fine, it will funtion at full speed,steady and quietl when applying 12v. However it does change speed while operating normally, indicating to me that something else is telling it what to do.
My question was about a little recirculating cabin air temperature sampling fan that controls the rest of the system in other M-Bs I've owned. Am I saying that correctly? Do the W123s have such a thing? I can't find the critter.
What is the little tiny grill top center of the dash? How does this play into the grand scheme of things? Should this little grill be pulling air past a sensor? There is no air movement here.
OK, I'll go plunder thru my 123 discs and see about learning some more about the A/C system.
More later, Thanks again,
Jacob