Audi Repair: A8L electrical draw, water ingress, switch problem

Question
My 2001 A8L has an electrical draw that drains the battery if the car has
not been run for 2 days.  It just came out of the dealer's shop after 3 weeks
and the mechanic's recommendation was to replace the instrument cluster
for $2,000+ because he couldn't identify the specific fault.  It seems to
me there is a switch problem that will turn on but not off, since the
instrument cluster comes on and works fine.  Thanks for you help.

Answer
The dealer is guessing.  Trying to secure a $2000 window to find the actual fault.  I would get someone who can troubleshoot the actual problem to give a second opinion.  They can be tought o find, it took me a month to find my Nav unit was causing my battery drain.  Most of these issues are due to water ingress, but they can be very time consuming.  You can use a current meter to measure the draw on the battery with the inginition off and key removed, the current drawn should be around 50 milliAmps, or 0.050 Amps.  Never turn on the ignition when the meter is connected since they can only handle a couple of amps; you can remove fuses to try and find the problem which reduces the problem to a known circuit.  In my case the radio fuse fixed the problem, but the radio was powering the NAV unit, so a replacement radio would have been wasted money...!  Let me know what you find,

Jan