Re: bypass exterior ambient temp sensor?

[James Marriott <marriott@micron.net>]

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?

> 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.

> 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.

> 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 . . .

> TIA,
> Elliott

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