Hi Jeff
I have the same problem no heat/blower/fan on my 1983 W126 300SD finally found it under the glove box, became a monkey, removed it, and there is nothing wrong with the unit, spins under 12V perfecto, so I re-installed. Now I am trying to remove the wood console dash panel to get at the ACC unit to remove, check and re-flow the solder joints, but cannot remove the wood panel yet. Removed/lifted all the switches, but panel will just not slip down. Any ideas?
This is not a daily driver (yet), and I am retired so it gives me something to do.

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The meek shall inherit the earth, the brave shall get the oceans