Good grief... I didn't take enough paper to write down all those error codes: in-car temp sensor error, ECT sensor error, freon pressure sensor error, sun sensor error, series interface connection to instrument cluster error.

The actual values are a little confusing. It appears they are a mixture of C and F. The chart on the link page says that refrigerant temp is in F, and the text on that page says that evaporator temp is in C. I'll know more when I do the test again while driving tomorrow.

It appears that pressing both Auto buttons at the same time clears the error codes.

If all those codes come back, it would seem to be the controller.