Re: Radiator Fan on High, 5KS

[Greg & Britt <image_one@earthlink.net>]

Dave C. wrote:
> 
> Dear Fellow Q-listers,
> 
> I suspect my radiator fan runs only on high speed and need help in
> diagnosing the problem.  It has run this way since I bought the car nearly
> six years ago, so I always assumed it was a single speed unit, until
> reading recent posts on this subject. 

It’s a three speed fan, 1st speed when A/C is on. 2nd and 3rd speeds
governed by thermo switch in radiator. There are variations on this,
depending on your VIN#.
Audi was aware of poor cooling and hot start problems with that year and
had modification kits to alter fan operation. You will need to check a
Bentley for proper wiring.

<snip>
> I checked resistance between all three terminals and measured 0 ohms.  I
> admit to being an amateur, but something tells me there should be
> resistance somewhere here.

The resistance is very low, your meter may not give you the value. The
fact that you had continuity between all three may be good ‘nuf check.
  
> Do I need to replace this item?  How can I tell for sure?

I’d suspect the thermoswitch on the radiator, if any coolant leaks on
those critters when changing the lower radiator hose they can go “south”
you. BTDT.
Disconnect thermoswitch connector on radiator and jump connection 2 to 3
for 2nd speed operation, 1 to 3 for 3rd speed operation. This should
identify if the thermo switch is the problem. Be aware that you may have
more than one problem! There are several relays and control units
involved in this circuit.
BTDT too. My 84 had a problem with the resistor and thermoswitch at the
same time.

Good Luck!

GT
84 5KT
87 5KCST