I have been steadily working on getting the 1980 280SE in road-worthy condition. I recharged the AC with freon and it worked well but I could not get the heat to blow. I spent 6 hours today with my wiring diagram and tested the servo, resistors, and the CC amplifier. I finally tracked it down to a bad solder joint on the amplifier board and took care of that.

While I had it out I added a small fan to keep it cool, as it looks like the failure was heat related.

As bad as a reputation as ACC II has, it's actually quite easy to diagnose if you take your time and understand what the system is trying to do.

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