Good luck, and do keep us posted.
Also, there are many posts on bad evaporators, and if you haven't done a search you might want to do so. In particular, there are some recent posts on which replacement evaporator to get (should you need to do so). Used to be that we were told to avoid aluminum evaporators as the factory-installed ones that went bad were aluminum. Now, the wisdom seems to be that using the "official" MB aluminum replacement evaporator is the way to go, since the old, failed ones apparently were a copper-aluminum hybrid and the connection between the two metals was the problem, not the aluminum itself (as I recall).