Air-con woes in 1991 L - maybe the engaging button

[enduro]

When I bought my L about 5 years ago the air con was terriffically freezing.

Over the last few years the aircon seems to switch off and repressing the aircon button seems to make it kick in for a a few minutes or so, sometimes only a minute! Thankfully I have a manual gearbox and can just click it on an off as needed, though it's a bit of a p*ss off.

When I press the button I have noticed there is a very quite sound like some gas mechanism engaging behind the switch. Is the switch much like the levers to control the heater where they are activated by wires and cag compression through those tubes at the back? Sometimes the blue aircon indicator light does not light up.

Has anyone got any experience in fixing the switch if this is what is the fault.

Can the aircon switch be removed without removind the whole dash unit? I may choose to do this prior to winter to replace the heater thtat has had to be bipassed.

All tips an ideas appreciated,