finally fixed fan woes

[Mike Posner <posne@cts.com>]

Symptom:  Radiator fan failed to come on any speed.I decided  I measured
11.8 volts at the red  hot wire at the radiator fan.  All fuses  both relays
and involved wiring must be "ok" I thought. Got to be  a bad fan motor.
Might as well replace the fan switch while I'm at it.  Put em in, and guess
what   no bueno, fan won't run on #1 speed with ac switched "on".  Also
the plastic radiator whose snout was successfully  repaired  2 years ago, 
decided to pop a tank seal , likely jostled during the r&r  practices.
So, in goes a modine all metal upgrade.  In the meantime I got lucky and
found the real cause of the no run fan (on my 90 200).  The fusible  link
which looked bowed but intact was badly corroded and while I was measuring
  each wire  I inadvertantly  grounded the brown wire
and the fan started and ran but wouldnt restart for me and the link
finally  cracked  from the spark  .  Wow, at last  an intermittant ground
problem  at the link . Wait, this isnt  all the Audi Gods  have in store.
When I gleefully bolted everything up  again the fan  fouled against the
shroud ( see previous post this week).  Grinding minute amounts off the
fan blades and the high spot inside the shroud gave only momentary relief.
The fix came from my local radiator  mentor  David Harris
of Harris Radiator in Leucadia, who guessed correctly that the shroud
may have distorted due to heat  and  my pulling upward on the shroud while
David  loosened and then retightened the top three shroud bolts
gave the additional  fractional clearance   to finally  complete
this job successfully.  Thanks again  to  to David ,  and to Huw on the list
whose advice not to file the fan blades, was only partially followed,
I only took off a little Huw!.  ( Too much  = out of balance}.   Hopes this
helps others on the list.   Mike Posner, Leucadia.