Seat Alhambra Diesel AC Problem

That's a tricky one. I had a similar issue with my old Volvo, although the symptoms weren't exactly the same. In my case, the A/C system would cut out intermittently. Have you checked the AC relay? Sometimes a faulty relay can cause the A/C compressor to disengage. Also, have you had the pressure switch checked? A faulty pressure switch can also cause the A/C system to shut down to protect the compressor.

Where exactly is the AC relay located? And is it something I can test myself, or is it best left to a professional?

The relay can be a bit challenging to locate depending on your vehicle's specific configuration. While you could test it yourself with a multimeter, if you are unfamiliar with electrical testing, it might be prudent to consult a qualified technician. A misdiagnosis could potentially lead to further complications within the A/C system. Given the error code already present, a professional diagnosis would likely be the most efficient route to pinpointing the root cause.

Took it to a local garage and they diagnosed it as undervoltage causing the A/C compressor to shut off. They replaced a faulty relay switch and cleaned some corroded connectors. Total cost was 240€, which seems reasonable. Air con is now ice cold again. Thanks for your help.