Take the top drawer out.
Can you see/hear the fan working.
If not working it may simply have frosted up (is the KGU32124 intended to be frost free?).
Once the trays are removed it is generally only up to six screws to remove the panel and get access to the fan and see the heat exchanger.
I have a cheap little stem cleaner (not sure if this should be recommended though) which cleared a similar job in a matter of minutes...or you could fully defrost for a couple of days.
Johnny Storm, February 2008