My serach has left me emptyhanded. On my greymarket 1984 250 Wagon ( like a 300TD but gas powered ) I have three dials on my center dash for heater control. The two outside dials control the temp and the inner dial controls the heater output level. The center dial will only turn a tiny bit, the blower motor itself is fine but this dial won't budge and I have forced it to the breaking point to get the heater to blow on the first level.

Any hints or links for pulling these knobs out to replace them or bypassing it . I am guessing it is a unit with three switches.

It is finallt cold in Alabama, time to fix this one...

That is the blower switch & there is a cable that attaches to it that controls the fresh air door under the passenger side of the dash. MOST of the time that cable siezes up & then damages the blower control switch.
You could try disconnecting the cable first.

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