Re: Radiator Fan on High, 5KS

[four.rings@MCIONE.com]

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.  (See Sandy Duffy's post, Nov. 27.)
> The fan cycles off and on normally re: engine temperature, but only at what
> I think is high speed.  I've found the resistor, a large blue metal plate
> with three wires behind the driver's side headlight.
> 
> My Big Question...how can I tell if this resistor is bad, and causing the
> fan to run on only one speed?
> 
> 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.

Actually it has 2 resistors in series. Each section is about 0.7 ohm, so
if you were using an analogue multimeter you'd get around 0 ohms.
Of course a good practice is disconnecting the POWER wires prior to
testing.
 
> Do I need to replace this item?  How can I tell for sure?

Run the engine, turn the A/C on, look at the fan. If the fan is not
running, one section of the resistor is blown. The fan should kick in
the 1st speed whenever the A/C is engaged. When one section of the
resistor goes, it takes both 1st and 2nd speeds out.

On my old 5000s I drilled the rivets out, took the resistor apart, found
a
break in that flat zig-zag heating element and brazed a 10x10mm Ni patch
over it. Put the mica insulator plates back in, assembled and riveted
the resistor back together and viola, zero dollars invested, works well
up to this day on (now my buddy's) car.
 
> FWIW, shortly after buying the car, on the first warm day, I became alarmed
> by the radiator fan's operation and took it to the local dealer to have it
> checked out.  They said it was normal.  I've since learned the hard way not
> to go to that particular dealership when I want help with auto repair.

It looks like that particular dealer does not know that on the 44
chassis Audis the syndrome of a fan, roaring on the 3rd speed only,
caused by a blown ballast resistor, could only be surpassed by a burping
leaky exhaust manifold syndrome in the frequency of occurrence. Stay
away from that dude.

-- 
Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- FINALLY!
Philadelphia, PA
USA