Radiator fan-1990 200tq Help

["Ron Frazier" <frazierx@concentric.net>]

My 1990 200tq is overheating.  The fan does not cut on under any
circumstances as far as I can tell.  I disconnected the fan and powered it
up with a 12v battery charger at 3 amps and the fan cut on and ran. I also
switched the the 3 relays around to see if any were bad but nothing showed
up.  I also checked the fuses. when I cut on the car, turn on the
airconditioner and the fan does not come on.  The after run cycle of the fan
did not turn the fan on when the car got overheated.  The wiring diagram in
the bentley manual is a little complicated.  What does the radiator thermo
switch do?  How does it relate to the basic fan relay?  How does it relate
to the AC high pressure refrigerant switch?  I am rplacing the radiator
thermo switch since I am now doing alot front of the engine maintenance.
Can anyone give me some tips on how to smoke this problem out.  One last
piece of potential info.  When i was leaving work,heading for the highway,
the AC would not put out cold air.  But after I got down the road I turned
on the AC and it put out a lot of cold air. I guess the AC is related to
Engine Temp.  As best I can remember the turbo water pump and the injector
cooler runs after the car is turned off.