Hello everybody, I am new on this forum so I apologies for any future mistakes.

I don’t have AC on my car so I want to install the system. I have all I need from a mechanical point of view but I have some trouble with the electrical part.

Can somebody please explain how the system works ? for example what does the pressure switches do exactly ?

After reading some ETM manuals I formed an idea but i’m not certain.

I wasn’t able to find the codes for the auxiliary fan relays K21, K22, and the compressor relay.

Can somebody help me ?

Also, how many amps does the auxiliary fan needs on full speed ?