540i problems with air con

[okorn]

Last year the air con worked and now it's not working anymore.
https://uploads.tapatalk-cdn.com/20241002/38242b52075a4e53034b5ba4874bc50f.jpg

I jump started it by connecting a cable to the main relay and then the compressor engages (cool air also!). But otherwise the lamp inside does not turn on and the compressor want start nor cold comes out. I tested with another AC ECU (which I can confirm is working) bot still nothing. The pressure switch (low and high) were also jumped without success. Any clue on what might be going on? The system was low on gas and I recharged it. Thanks!


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[thenjnick]

You mentioned everything works when you jumped out the relay. Have you tried replacing the compressor relay and all related fuses? The green light on the AC button should only be backlit if the compressor clutch is engaged.


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[okorn]

You mentioned everything works when you jumped out the relay. Have you tried replacing the compressor relay and all related fuses? The green light on the AC button should only be backlit if the compressor clutch is engaged.


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Yes. That was tested and not working :(

Any other clues?


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[okorn]

I managed to fix it! This thing here was loose and that was the reason for the air con not working. When you turn the wheel of the fan, that should also turn in order to give the ECU the signal "ok you can turn on AC now" but as that was not the case it was not working.

730646

[shogun]

nice fault find, thanks for the info, this will help other members in future.

[okorn]

nice fault find, thanks for the info, this will help other members in future.

Yes, hope this helps! It was driving me crazy.