Heater problems. HELP!!
 

Hello everyone, I have a 2002 Boxster and am having problems with my heater. Every time I set it to high it just drops back down to low on its own. If I hold the button down it will stay at high but that makes it difficult to shift!! As soon as I remove my finger back down to low it goes. Is the unit itself shot? Any help would be greatly appreciated! Thanks in advance for your help!!!