Gentlemen (and ladies!)

I have just taken possesion of my first MB (1990 500SL) so am new here. Please excuse any proceedural faux pas or breaches of etiquette.

I have two trivial questions to start with.

1) The light switch is not illuminated. I guess this is not right, and if so, how do I get to the bulb which I presume has blown?

2) On a closed throttle I can hear a gentle hissing noise, which sounds exactly like tape hiss from a speaker(and appears to be coming from the front right corner of the dashboard (right hand drive)). However, as soon as throttle is depressed, hissing vanishes. Any thoughts?

There are several more trivial points I need help with, but I guess I will feel my way in gently, not yet knowing if I am in the right place.

TIA

David