Hi,

like others have said, just wire a switch in if you don't want to replace
the thermoswitch in the rad.  Should be easy by taking two wires off the
rubber covered connector on the rad and running wires to interior through
any of the other holes there. Make sure the switch is illuminated, to remind
you to shut off fan since it's power supply is normally 'alive' all the
time. Connect up the low speed side, unlikely you will ever need the high
speed working, and it is too loud for continous use. Just flick on the
switch when you hit slow traffic or the needle gets clear above the LED in
the temp gauge.  I'm surprised that somehow both high and low temp parts of
the thermoswitch have failed, perhaps check the circuits somehow for further
probs, may be harder because of mechanics hack job.  bye, Tim

PS: check junkyards for Audi 5000 rad fans, they _look_ identical, and
serial numbers match down to last position.