bypass exterior ambient temp sensor?

[Elliott Potter <epotter@abraxis.com>]

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.  The irritation
is that when it gets below a certain temperature outside, the A/C won't
turn on.  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).
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?  FWIW, it has to be bypassed and not disconnected, because
disconnecting it will cause the A/C to not operate at all.

TIA,
Elliott