Hi,

I am having problems with my AC unit and dropped lines on my
instrument display. Hope the board can help with some insights.

Car
A4 1.8T, Automatic, FWD manufactured in September 2000 (2001 Model
Year) . This is a UK Spec with steering wheel on the right hand side
of the car.  Purchased car new and I am now at 75,000 kilometers (45K
miles) Car services at dealer every 10,000 to 12,000 kilometers. The
engine code is APU (I think close to AEB)

PROBLEM 1 - AC COOLS INTERMITTENTLY.
My AC works reasonably well at times and not at all on other
occasions. Sometimes the system cycles every 30 seconds or so where it
literally blows hot and cold.  If you are not moving you can even
detect the increased engine load when it is cooling.  When the unit
reverts to heating the load on the engine decreases.  It seems that
the cooling system is turning on and off all on its own, leaving the
blowers to blow in ambient air.  Often when cooling it switches to
Econ mode all on its own.  When that happens I have to turn the unit
off for about 30 minutes before it will cool again.

My dealer says that there is probably a leak in the system and I will
have to replace some expensive part.  Not sure if I buy this since a
leak would degrade the system totally and it would not work some of
the time.  I have had this "leak" for a year now and the system still
works most of the time.

Dealer has never serviced the AC unit or even told me it needs
servicing. Since I am not a car buff and I did not, until recently,
know that you needed to do anything but top up the refrigerant.  I am
now finding out that the unit needs "oil" as well as refrigerant.  I
know that oil has never been replaced.

Q1 - Is there any way to test for a leak without disassembling the
entire dash? I just got one of those Audi CDs off of eBay and I see
references to leak tests but no instructions on how to perform one.
Q2 - if it is not a leak, what could it be?  An electrical problem?
Q3 - if a part is bad, what are the appropriate part numbers for my
A4?
Q4 - are the parts the same in the US and the UK?

PROBLEM 2 – MISSING LINES ON INSTRUMENT DISPLAY
My instrument display is failing line by line. I am loosing entire
horizontal lines of pixels.  Sometime they come back, but then another
line disappears.  Up until recently only one or two lines gave trouble
but now more than 20 lines are acting up.  Two verticals lines are
also starting to fail.

The problem is at its worst in the morning when I turn on the car.  At
that time as many as 20 lines are missing. As I drive the car many
(but not all) of the lines reappear.

My current hypothesis is that moisture (it is the wet season here) is
condensing on the circuits behind the cluster and causing some
corrosion.

Dealer says this happens to all Audis and a new cluster will run me
about US $2,000K - not including labour!!  This is not an option!!!

The other display units (time/date, radio, odometer, etc are fine)

Q5 - Is there any way I can get behind there and clean/replace leads?
Q6 - Is there a way I can replace just the LCD display rather than the
entire cluster?
Q7 - If I have to replace the cluster, what is the part number and
what is a reasonable cost?

Nuff Respec!! (Many Thanks and Much Gratitude)

Simon