[s-cars] climate control issue again

[Paul Heneghan]

I had problems with my CC head last month - turned out to be a blown 8.5V
regulator, caused by a short circuit temperature flap motor.  When I took
the CC head apart, I noticed that all the plastic clips that hold the facia
to the switch circuit board had broken, allowing the facia and circuit board
to separate.  Although in my case, the buttons still worked, this could
cause the problems you describe.

I started all of this, because I couldn't control the temperature at all on
both cars, and on one of them, I couldn't get any air out of the face vents.
I was getting some 08.5, 11.5 and 13.5 codes implying one or more defective
flap motors.  I did both cars at the same time, so I serviced six flap
motors in total.  I had three flap motors that didn't work at all (one being
a short circuit, the other two were open circuit), one flap motor that
needed a service, and two flap motors that appeared to be OK.  Of course the
short circuit temperature flap motor had caused the regulator in the CC head
to overheat, and although the spec sheet for the L4940V85 8.5V regulator
talks about thermal protection, it cooked itself.

The only good side to all of this, is that I saved so much money fixing all
the motors and the CC head, that I bought myself a dual bench power supply!
I don't know how much CC heads are new, but they fetch quite high prices
(GBP 50 - 100) second hand on eBay.  Flap motor actuators seem to cost from
about GBP100 to GBP200.

For those of you with unpredictable/intermittent air delivery and 08.5, 11.5
and 13.5 error codes on the CC head, I've made a start on a write-up on the
process.  It's not finished yet - I need to add a description of the
regulators in the CC head with some pictures.  It's at:
http://www.eveshamsquash.co.uk/audi/climate.html

Paul

-----Original Message-----

Message: 2
Date: Wed, 5 Oct 2005 16:34:55 -0400
From: Matt Molyneux <mmolyneux at gmail.com>
Subject: Re: [s-cars] climate control issue again

I have the same exact problem from time to time now! The CC had done this
before maybe a year or so ago, but in the last month it has crept up again
and acts like this almost all the time. The one thing I have discovered is
if you hold a button that doesn't work, or kind of jam at it, sometimes it
registers and works (as if there is a bad contact back there). Other than
that, I often have to wait a long time for the buttons to mysteriously work
again, sometimes in a few minutes, sometimes a day later. It's really odd, I
hope there is a fix out there.

On 10/5/05, forrest bradshaw <sola4est at yahoo.com> wrote:
>
> the next day after the first issue the CC unit worked normal again, but...
> climate control again froze last night, only 3 buttons responded. -temp,
> floor vent and recirc button. it also rained last night.
> could there be a wiring issue or should I be looking for a new climate
> control unit?
> this is gonna get annoying if this happens all the time