Don't know if this helps, but when my ignition switch hangs up after starting, that is the exact display that I get. Defrost, no matter what the output is set on, 0C no matter what the temp is set to, manual fans, and the display is gray instead of black. Wiggling the key restores the display. I know that may not be your issue, but a loose or poor connection, would mimic that situation. Are there more than one power inputs to the unit?