gas guage questions

[Elliott Potter <epotter@abraxis.com>]

I have a few questions about the operation of the gas guage in my 93
90CS:

-I assume there is a float arm in the tank controlling a rheostat or
sender.  I've seen 3 different styles of senders, but have no reason to
believe that Audi's will be the same.  What does the sender send when
the tank is empty?  When it's full?  Is there some way I can check this
myself without reducing my beloved Audi to tiny pieces strewn about the
garage?
-There's a small round access panel in the trunk on the right side
behind the seatback.  If I open this, will I have access to the wires
from the sender to (carefully) check this myself?

TIA

Elliott