Re: bypass exterior ambient temp sensor?

[Elliott Potter <epotter@abraxis.com>]

James Marriott wrote:
> 
> Elliott Potter wrote:
> >
> > Now that winter is arriving again, I have another odd irritant/endearing
> > feature of the Audi climate control to b*tch and moan about.
> 
> > The car is a 93 90CS, with an automatic climate control.
> 
> Is this R12 or R134A?
 
R12.

> > The irritation is that when it gets below a certain temperature outside,
> > the A/C won't turn on.
> 
> The reason for this "malfunction" or "deficiency" is that below about
> 35-40 dF (2-4 dC) there's pretty much no moisture left in the air. If
> it's not there, why try to remove it? Also, especially if it's a 134
> system, it is pretty helpless at these low temps by design. Not Audi's
> fault, just a fact of the thermodynamics.
 
Here in Atlanta, we get this a lot--it's not quite raining, just a kind
of mist in the air, just 2-5 degrees above freezing.  The windsheild is
fine when I get in the car, but as soon as it turns on, the CC sends a
big blast of warm air up to the windshield, and voila--instant fog.  I
can never seem to hit the buttons fast enough to prevent this.
The other reason I want to disable the sensor is that Atlanta is also
the Land of Deisel and Burning Oil, and recirculate won't work unless
the A/C is on.  Just a little annoyance, you know...

> > That makes limited sense, but it also means that I can't flip
> > on the A/C for a quick windshield defog if it's cold outside (BTW I
> > almost took off someone's door last night because of this).
> 
> Make sure the window's clean; if you haven't cleaned it in about two
> weeks, it's not. And try not to breathe on it (sounds dumb but roll down
> the window and pretend you're smoking a cig, etc) 'til the fan is going.
> 
> > Anyway, does anyone know where the exterior ambient temperature sensor
> > resides, or how to disable it?  Also, what would be the side effects of
> > disabling it?
> 
> On the 4kq it's under the cover behind the firewall (under the hood,
> like with the wiper motor, and on the right side). Yours is likely the
> same place. Mine is a little, black, marble-sized component with two
> wires. Dunno if it's normally opened or normally closed. The "fix" for
> mine would be to either disconnect or short the wires, depending on
> which way it's configured. YMMV.
 
Well, could it possibly be in front of the little aux. radiator between
the fog lights?  There's *something* there, about the size of a marble,
with two fat wires coming off it.  Seems like an odd place, right next
to a radiator, but who knows...

> > FWIW, it has to be bypassed and not disconnected, because
> > disconnecting it will cause the A/C to not operate at all.
> 
> Dan Masi and I went _WAY_ down this road last year. Please check the
> archives. Call it a "feature" if you like, but there's no fix . . .

I'll check it out, thanks!

Elliott

> > TIA,
> > Elliott
> 
> cu
> James, BSME
> Boise, ID
> '87 4kq
> '86 4ks
> '64 Falcon (no AC, but top goes down!)