climate control question
 

hello i need help please. on my 93 mercedes 300se (w140) when i run the heater on high speed. the control panel gets stuck on high wont turn off also the other day. i had the heater on, it just turn off and wouldnt come back on. i replace the blower regulator about a year but now im kinda thinking its the control panel any ideals is greatly appreciate thank you.