Fan runs with heat on

Ben Walker benwalker at
Thu Jan 9 10:11:09 EST 2003

 I think I can replicate the problem but have no solution. Mine does the
same thing when in AUTO mode.  Engine fan runs after a few seconds and shuts
off when climate control is shut off.  does not do this when any other
selection is made from the climate selector.

It causes the temp guage to fall (FLATLINE) and causes other engine poblems
such as rich run.  All in weather so cold that the inside windows will
freeze over.

My problem also exists when in econ mode and travelling at highway speeds.
If I can stop and idle a few minutes or am in stop/go traffic, the temp
guage acts normally and I have heat.

My two abes.

1990 90 Non-Q
----- Original Message -----
From: "Joshua Van Tol" <josh at>
To: <Navistrpwr at>
Cc: <quattro at>
Sent: Thursday, January 09, 2003 7:47 AM
Subject: Re: Fan runs with heat on

> On Thursday, January 9, 2003, at 03:13  AM, Navistrpwr at wrote:
> > heater on my brother's 5k.  One thing I noticed is that the 1st stage
> > cooling
> > fan always runs with the climate control on, regardless of whether or
> > not
> > it's set at 60 F or 90 F.  This isn't normal, is it?  I'd say it
> > isn't, as
> > the engine never warms up sufficiently with the climate control on.  I
> > talked
> > w/ the parts guy at my local Audi dealer and he said that the system is
> > getting an A/C signal somehow.  He pointed to the A/C control head
> > and/or the
> > temp sensor on the evaporator housing as the culprit.  I've replaced
> > the
> > programmer, control head, and temp sensor with units I got at the
> > junkyard to
> > no avail.  I replaced the radiator fan control switch with a brand new
> > one
> > (and am glad that I did so...I didn't realize the 2nd speed fan was
> > malfunctioning, it would always run at high speed...fixed that
> > problem)  I
> > also tried disconnecting the high pressure switch on the condensor to
> > see if
> > that would be causing any problems.  I'm at a loss for what else to
> > try.  The
> > only way I can get the fan to shut off is to remove the 1st speed
> > relay in
> > the fuse box under the hood.  However, I put it back in so the
> > after-run fan
> > will still work.  Any ideas as to why this fan constantly runs?
> >
> What's the outside temperature when this happens, and are you in "econ"
> or "auto"? In Auto, the fan runs, because the ac clutch could become
> active. I don't remember  if it cuts off when the temperatures are too
> cold, but it may. Try putting it in econ and see if it still has this
> problem. Also, have you checked the heater valve, and whether the
> heater core is plugged up? Finally, you should probably see if when the
> heat is on "hi" the motor in the programmer drives the bowden cable all
> the way to the hot stop.

More information about the quattro mailing list