Need Advice About A/c In E34 Just Bought.

[bimerguyCW]

Just bought a great '95 530i with a rebuilt engine and the prev owner had the A/C evacuated before engine removel so I had it charged and they had to jumper the compressor at the relay socket to charge it. Even with that the vents temp was 95 F with compressor on and higher with it not jumpered.

The control buttons for a/c, recirc., etc. do not light the LEDs and not able to activate the a/c with them obviously.

What does this indicate? Where would I start to begin breaking down the system's fault and repair the item(s). Is there a fault code reader that is worth buying/renting/getting from shop to reliably diagnose and do the repairs myself?

Thanks for the advice.