JD, the full speed voltage is 9 volts.

While checking prices and part numbers to buy a rebuilt pushbutton CCU, I pulled mine out to double check the number, which was indeed 124 830 33 85. I unplugged it, cleaned the pins, plugged back in, and voila, it’s been working for a day now. That could be good luck or I merely repositioned bad Bosch cold soldered connections that will some day lose contact again.

I also found in my parts bin a unit 124 830 02 85, which came out of an early 124 car from a PnP and has a Celsius scale. If my CCU starts acting intermittently again, I will swap that one in and send mine to JamesDean to resolder.

FYI, rebuild units are priced from about $250 (auto****az) to $500, and I found a MB factory part for about $700.

Here’s a thread about using 33 85 and 02 85 in a 124 car:
http://www.peachparts.com/shopforum/diesel-discussion/278238-climate-controller-part-number-question.html