A/C Control Problem on 1999 Lexus RX300

My A/C is working, in the sense that it is blowing cold air. Yesterday while the car was running, it just randomly auto-changed (best way to describe it) and no longer responds to my changing of the knobs/desired output of A/C.
After some simple googling it seems it 'could' be the resistor? Or is it a problem with the digital display? Thank you.

Asked by for the 1999 Lexus RX300