4kq overheating! help

["Gregory C Mayer, Hydrologist, GW Spec, Atlanta, GA "<gcmayer@usgs.gov>]

Hello Audi Fans,
I am having cooling problems with our '84 4kq and would appreciate some
kind advice.  Kid drove it from Atlanta to Savannah for St. Pats and
brought it back worse for the wear.  The engine overheated on them as
they got back to town, but did not need water.   After numerous cooling
stops they finally got home.  I found that the rad fan would not come
on at all.  I was able to jump wire the fan and it works fine.  My
problem is that I can't find the thermoswitch that controls the fan,
and I'm confused by Bentley.  On page 19.5 the two page illustration
shows with labels two thermoswitches, one for the fan and one for AC
(which this car has).  It also shows a simple flange where the return
hose goes into the head.   This does not match my engine.  Must be
another 5 cylinder. I could find no switches anywhere in my cooling
system other than the two that are in the return hose flange at the
head.  One two wire switch faces up and the other down.   Is one of
these the thermoswitch for the fan? The wire colors don't seem to match
the description on page 97.56.  How can I test this? Also I see in the
electrical section on page 97.56 a description of a rad fan relay.  How
can I test this relay, and is it under the dash?
How is the fan controlled?
Thanks for your time and information.
Trying to not get hot...
Greg