[s-cars] Re: heater fan a thon

[Franco Barber]

On Fri, Jan 24, 2003 at 06:13:57PM -0500, Lee Levitt wrote:
> Bill writes:
> >
> > Are you sure it's the heater fan? Does the noise vary with the fan
> > speed. Reason I ask, is that the miniature fan that draws cabin air in
> > for climate control purposes sometimes makes noise on my 94 S4. Fan
> > pulls air though the tiny dash vent to measure the temp. Happens very
> > rarely and hasn't happened in a long time, but, first time I heard it, I
> > thought the heater fan was going. Varying the fan speed had no effect on
> > the noise, but turning things off completely stopped the sound. Might
> > check this out prior to major surgery.
>
> Nope, I'm not sure. The sound does not vary with fan speed.
>
> Should I just assume that it's the primary fan and go ahead, or is there a
> way to diagnose which fan it is?

I have the same noise on my 95 a6q.  I also think it's the miniature
fan, but I'm not sure.  The noise is very high pitched, and it
does not vary with ventilator fan speed.

I have a cunning plan to diagnose the problem:

The miniature fan is reached by pulling out the instrument cluster.
It's on the right side of the opening with the cluster out, up
above the opening.  There is a connector right there with 2 wires
that power the mini fan.

My plan is to pull this connector and insert some sort of wire harness
that leads to a switch that I can use to cut power to the mini fan
on demand.  I will run the wires out the bottom of the dash and
leave the switch in a place I can get to easily (say beneath the ashtray.)
I hope I can do this without having to cut any wires in the original
harness.

Then, when the noise happens (and for me it takes 20-30 minutes of
driving AND bumpy roads) I can open the switch to kill the mini fan.

If the noise goes away, I know it's the mini fan.

The part number for this mini fan is 4A0 820 545.
Any body know roughly what this goes for at the dealer parts counter?
If the fan is cheap enough I'd just replace it and be done with it.
Not having to open up the instrument panel one more time would be
worth something in itself.

Franco

--
Franco Barber                   feb at febsun.cmhnet.org
95 A6Q w/Gamma CD mit RDS!      Columbus, Ohio  USA
95 A6Q 5spd w/HCB-30 bluetooth car kit!