W124 climate control 2 stage shut off

[Tom300CE]

Hi Guys,

When I bought the car (88 300ce) I discovered that whole climate control system can malfunction in 2 ways:
1) Non of the 3 buttons work when you press them, lights in corner are out, full heat is on.
2) All buttons don't work but lights at corner are on, also full heat is on.


As soon I shut off the car and restart the car everything works again, aircon is cold, heat is how you set the wheels.

Any idea what can cause this kind of problem or what to check?

Regards,
Tom