Hey all!
So I've been putting getting all the old bits and pieces sorted on this new to me 1988 930 cab.
I went to use the heater the other night, and once I turned the center dial (between the seats), I could hear it move the lever that operates the cables, but no fans anywhere turned on.
I have the blowers in the footwells (cleaned up, new fuses, and they spin great on the bench). A new blower in the frunk pulling in air. 
But I cant seem to get the heater fans moving. Does the car have to be running (I know it does to produce heat, but want to just hear the fans spin) for the fans to come on? Does the center dial just go full close and full open?
Thanks for any tips! Its getting cold here in Colorado... lol
Best,
Bill