I have done a search and found some info, but not quite this problem.
All components of my climate control system used to work (last week).
Now, I get nothing when I turn on just the defrost fan (all three settings) without A/C.
When I turn on defrost fan with A/C, only the third setting produces results (air and cold).
This happened suddenly, overnight. Any thoughts? Alex

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"Frau Blue Car" 1980 240D think Frau Bluker, cue the horses, formerly known as "China" from JimmyL
"Gunther" 1982 300D.....Turbo!! A/C!! Sunroof!!
"Fraulein" 1975 240D----Donated to NPR