Orange Button?

[Koopman]

Someone recently asked me to find an round orange button that fits in the hole just below the hazard switch. Is this a part that every E9 has?
I found one and it is called a Heating Switch. What does a heating switch do?
Thanks for any info.
Koopman

 

[aearch]

rear window

 

[Koopman]

rear window

rear window

Thanks Loads.
Koopman