AC is WARM

My AC is ALWAYS warm and i am not familiar in this field of repair. This car has been in the family and has had a history of AC problems. I dont know if this is a seperate problem but when i turn the AC (or heat) on i can hear a hissing noise which sounds like a vacuum leak or something. Somebody PLEASE help because i CANNOT STAND being hot in the summer and would like to get this fixed before its hot again...

The hiss you hear is likely in the vacuum-controlled heater/AC controls under the dash. One could be off or broken, especially if the hiss remains constant - in which case, that's where I'd look. The lines are typically of the hard plastic type - which get old and brittle and do not take much to break.

Can you hear the compressor clutch (fairly loud clicking sound) when the AC is engaged? Have you had the opportunity to put a manifold gauge set on the system?

mine did this as well when i first got it, i needed to get a new vaccum control switch, which is located behind the ac controls and has all those little rubber tubes connected to it.