My S2 coupe bit of a rebuild and repair thread.

[psiconauta911]

Mine is a 94 ABY with climate control and is R134a to,

and sorry for the hijack but on the subject,

mine was working fine and the day after the snowflake lights up and nothing, the compressor doesn´t start, the fan doesn´t start and no cold.
Looked at the fuses and relays on the fuse box and all normal, looked with a darklamp at night for major leaks and found no leaks at all.
I wasn´t using it for a while and first day I used it it was all normal, the day after it went kaput.
Normally when it´s low on R134a it still works but I charged last year and it worked fine the day before it stopped working, everything else its ok.

When I push the snowflake button it lights the snowflake on the panel but that is all.

Are there any fuses or relays under the dash I should check or do you guys have any idea of what could it be?

[B5NUT]

Is there any diagnostic on the digital climate system?

Not sure about under the dash for fuses. The only ones I know about are the main fuse box in the engine bay. Fuse (17) and top right relay appears to be for the A/C system. Also check the fuse and the relay below circled in yellow. These has been removed on my car and I had no low speed fan when I pressed the A/C button. Could be worth checking all the fuses and relays relating to fans and A/C.

[psiconauta911]

Thanks, I´ve cheked the 17 and it´s ok and mine doesn´t use the top right relay, tomorrow I´ll chek the other relay and fuse 20 as you´ve circled.

I´ll run the diagnostic see if shows anything.

[struikie]

Is the clutch on the pump engaging?

JW

[psiconauta911]

Is the clutch on the pump engaging?

JW

No, apart from the snow flake lighting up nothing happens, it was working fine one day and the next its like that. I´ve checked the fuse 20 and it´s ok the relay 214 that B5NUT circled I removed it and looked fine, I am going to replace it with another one and see if it makes any difference, I´m waiting for the day to cool down a bit to run the climatronic diagnostic test and see if something comes up.

About the clutch engaging, normally when the system is low on R134a you notice the clutch disengaging/engaging more often but the day before it worked fine without syntoms that is why I´m searching for an eletrical cause if it is without R134a it must be a massive leak and I was expectig to see some evidence with the dark light, also I´m not sure but I expect, probably wrongly, that when it hasn´t R134a it turns the snowflake off after turning it on.

[struikie]

I had mine not working because the connector near de pump got disconnected.
But I don't remember if the snowflake stayed on or not...

JW

[psiconauta911]

Have looked around and didn´t find anything disconneted but did the diagnostics and had a e2 code on channel 52 that translates to "A/C Refrigerant Low Pressure Switch (F73)",

searched the web and found this thread on quattroworld https://forums.quattroworld.com/s4s6...ds/29596.phtml ,

the same syntoms and the same codes, so I suppose I have one of 3 things,
1st- a low refrigerant and that means a massive leak some where,
2nd-a malfunctioning low pressure switch and if so I have to find where it is and have it replaced if I can´t do it myself because I think the AC as to be discharged before changing it, if I bridge the wires on the connector and it works than is the low pressure switch that is kaput
3rd- bad connection in the low pressure switch or in the wiring to it, as before I have to discover where it is and see if it got disconnected or have some broken wire.

Does anyone knows where the low pressure switch is located on an ABY avant with climate control?

p.s.: sorry B5NUT for keep on hijacking your thread.

[psiconauta911]

Went to ETKA and after searching a lot found the low pressure switch in the most dificult place it could be behind the HAVAC system against the firewall I´m fecked!

I hoping the AC lost the refrigerant and as an easy leak to fix although probably not

I went to the car and took the cover off the charge valve in front of the radiator and pressed the valve heard a very faint shhh that lasted for a second or two, no refrigerant and no pressure, have to find the leak now, I´ll take another look at night with the UV light and see if I can find the leak and solve it prior to have the AC refilled.

[struikie]

There is a saying: "that is why mechanics hate engineers" hahahaha
The pressure switch is really really badly placed.

JW

[B5NUT]

I looked for the low pressure filling port the other day, and could I hell as like find it. Then I saw this photo on FB. No bloody wonder no one can find the port or the sensor.
1-heater.jpg
The approval for that design must have gone all the way to the top of the ministry of crap design.

[psiconauta911]

Yes it´s just stupid!

[psiconauta911]

Took the car today to have the AC charged, the machine run its program without detecting any leaks, but in the end a major leak was audible coming from the lower part of the condenser and thursday the car will go in the shop to remove the undertray and locate and solve the leak and have it charged again, the refrigerant was recovered, well most of it at least, and at least is a leak in an easy to reach place not in the dreaded, under a mountain in the pacific ocean, low pressure switch thingy.


The leak is around the nº11 area, maybe is an easy fix!

[B5NUT]

More like a holed condenser, if it is then it's easy enough (but not cheap) to replace. However it could the the pipe. I've just had to fix that pipe yesterday as I found a hole in it So had to degas the system, weld up the hole and regas! Yet more money

[psiconauta911]

Hope its a tube not the condenser... fingers crossed.

[B5NUT]

I would rather it be the condenser. The pipe from the condenser to the pump is no longer available and the nut holding the pipe to the compressor is usually stuck fast and you could end up snapping of the connector on the compressor! Seen at least 5 compressors that have been destroyed that way. Either way good luck.