Driving my car today I noticed that my AYC was making some noises then cut out then the red AYC warning light came on, could that be the symptoms of having the wrong AYC pressure switch?
I would imagine so, yes. The BEST person to ask about it is MPBVR4, he is on cvr4 and lives in the UK. His job entails something with switches and what not and he sells both types of switch to people in the UK. He will be able to tell you why it is happening, and will be able to sell you the right one.
There should be a bit of a whine coming from the AYC pump when it is pressurizing the system, but there should never be any squealing. If there is, your clutch pack fluid most likely needs to be changed.