A while back there was a post about the ability to view actual values and other diagnostics through the A/C Pushbutton Controller. I mentioned an article I wrote that would come out in April. That issue of "Import Car" has now been published and can be viewed at http://www.import-car.com
To see the article click on Featured Articles and then Mercedes-Benz A/C Diagnostics.
BTW the charts shown were condensed from information on 210 chassis E320s. There are similar diagnostics for all models with LCD displays. The earlier cars are a little different but all have some diagnostics available.