Turning off the fan does not turn off the a/c system. The part of the compressor farthest forward turns the compressor. There is a clutch that engages that connects the belt driven pulley to the front plate thus turning the compressor.

The compressor must be good or you would not have cold lines and cold air. To turn off the a/c you need to press the button with the O on it.

With no more info than you wrote here, it sounds like the only thing wrong is that you are not operating the system correctly. Do you have the owners manual?

Good luck,