Just had a sudden failure in the AC in my '90 Westy:  Was running fine
two weeks ago (got me through some 100 degree weather just fine) and I
think I used it briefly last weekend.  Yesterday, it turns on fine, can
feel/hear the compressor kick in, but no cooling at all, just blows air.
Checked fuse 12, it's fine, and AC shuts off when it is pulled, so not
there.  Are there any other fuses that could have gone or anything
obvious that I'm missing, or, am I in for a session with the dreaded AC
mechanic???