e36 air con trouble

Has anybody had this trouble, i need some ideas:)

When i press the button to start the air con going not much happens, the light comes on and i get a sound behind the dash but there seems to be no action from the engine bay.
How many connections to the ac pump are there? i can see one and it does look dirty ( have gave it a wiggle bout nothing)
Fuses look fine, not sure bout the relay, can it be tested? how do i know it is faulty?
The drive belts have good tension.

Any ideas anyone, its finally starting to get hot over here :)


Simon

as long as the control panel lights up and shows temp. displays the problem is probably a low freon level in the system. take to someone for a quick check of that, if it's empty the system, obviously has a major leak, if it's just low a recharge should fix it.