Aircon Notworking

Hi all our aircon has stopped working. Nothing happens at all when I push the button.

I read in another post that there is a failsafe. My understanding of A/c is that the a/c belt is driving a wheel all the time but the pump, or is it a compressor? is engaged electrically when you turn it on. Does the failsafe stop the compressor engaging and also stop the A/C light coming on on the switch?

I've got it booked in for a recharge but a question is can it even be recharged if it won't engage?
Some very scant reading of the repair manual mentions running the engine at ?,??? revs with the A/c switched on. I'll print it all out this w/e so I can read through it better.

Also how low should it be to qualify for a cut-out? I can see that there is fluid in the system through the inspection glass.

All pointers appreciated.

Thanks
Mark

When the gas is low it will not engage this saves the compressor overworking and damaging itself.
The switch should activate then deactivate. Lift the engine bay cover locate the AC compressor, start engine and observe the pulley when you switch AC on, if it moves (engages) then moves back that will be low gas, if it does not move then that will be a malfunction of the electrics.
Check as described above.
Check AC solenoid clicks when AC switched on.

Or take it to an AC specialist not just a recharge place.

Thanks Clive will do that's very informative.

I know it may be a silly question but have you actually checked the A/C Fuse and/or A/C Relay are OK?. Sometimes, even for Mechanics, they can be the most overlooked yet basic things to go wrong.
Running direct 12V to the Compressor Terminal will tell if the Clutch is cutting in or not.
Check that the Compressor is not seized. Rotating the Compressor Clutch should feel resistance but easy to turn.
There's too many variables that can cause an A/C System to malfunction. Low Gas, Faulty Pressure Switches, Resistors, Fuses, Relays, Thermostats and On/Off Switches. Even the ECU can cause problems. Bad Earthing. Unless you're confident you can check all these items best off letting a professional check it out.