rad fan wont stop

[millertyme]

I did some more testing and found that the thermal switch on the rad, hi
and lo speed switch, is bad.
All three of the terminals are shorted.  This of course will cause the
fan to run all the time
The switch will be in tomorrow, and I will post the results
Thanks for the help
Later
Brian


-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com] On
Behalf Of Tom Christiansen
Sent: March 24, 2003 23:45
To: millertyme; audi mailing list
Subject: Re: rad fan wont stop

Brian,

>I have an '87 5K turbo and I can't get the rad fan to NOT run all the
>time.
>My dealer told me that there are a set of 3 diodes located on the frame
>rail that also controls the fan.  Does this sound right?

They aren't diodes, they are resistors. And judging from your
description
they also work! The resistors are located on the LEFT frame and look
like a
piece of angle iron (typically blue or pale green) with three studs/tabs
coming out of it. The studs have some rather hefty (8-gauge, I'd think)
wires attached to them. If the resistors are bad, the fan will only run
at
the highest speed.

If I remember correctly, there's a separate thermal switch controlling
the
fan. I forget if the switch controls the fan directly or if it goes
through
a relay. I bet either the controlling thermal switch or the fan relay
has
gone bad. Also note that if you have the AC on, the fan will come on at
the
lowest speed when the ignition is on regardless of engine temp.


Tom