Helpon AC and Instrument Display Problems

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
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When you get the system regassed they will use a ultra violet dye, which when leaked out, shows over the engine bay.

Could be a faulty Climate module, they do go wrong, ebay is a good place for a new one

Yes they should be, at least most parts are.

Not easily, this should be a warranty issue, is you car out of warranty? if it is ask you dealer who services the car to sort it

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Simon,
I have an '00 A6 which is starting to lose lines. I asked the same question on another ng with response that it is the connections inside the cluster. Apparently, it is fixable by replacement as working inside the cluster is close quarters. Pricey option to replace. Alternative is to turn the display off (I know that's the ostrich approach). No good solution.
GRS

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