AC button problem

[Shasha127]

Hello 
Yesterday drove my 2010 M59 1.6HDI all day with AC on and it worked good. On steep hills im shutting down the AC compressor pressing the AC button on the tash to help the small 75hp climb up and turning it back on after iv passed it. 
The AC button and AC system worked fine all day on 30c+ outside , but in the evening on the way home (about 26-7c outside) at some point iv tried to turn on the AC again but the button wont react and wont light up the small yellow light that shows the compressor is engaged. pressed it few times until i got home and nothing - the button wont light up and the AC compressor wont engaged.
Today i went to start looking for the issue on the system, first thing i did was starting the car and turn on the AC system and now it works fine again as it should. pressing on the AC button turns on the compressor and cold air is getting in.
At no point the car overheated - my temp gauge sits very steady on 1 line under the middle point (90) and gets there very rarely.
I dont want it to happen again as it will probably will at the least comfortable situation, so im asking what could be the cause for this issue?
Thanks

[Bootlebarth]

Hello 
Yesterday drove my 2010 M59 1.6HDI all day with AC on and it worked good. On steep hills im shutting down the AC compressor pressing the AC button on the tash to help the small 75hp climb up and turning it back on after iv passed it. 
The AC button and AC system worked fine all day on 30c+ outside , but in the evening on the way home (about 26-7c outside) at some point iv tried to turn on the AC again but the button wont react and wont light up the small yellow light that shows the compressor is engaged. pressed it few times until i got home and nothing - the button wont light up and the AC compressor wont engaged.
Today i went to start looking for the issue on the system, first thing i did was starting the car and turn on the AC system and now it works fine again as it should. pressing on the AC button turns on the compressor and cold air is getting in.
At no point the car overheated - my temp gauge sits very steady on 1 line under the middle point (90) and gets there very rarely.
I dont want it to happen again as it will probably will at the least comfortable situation, so im asking what could be the cause for this issue?
Thanks

The computer system on aged Berlingos seems to suffer from mild dementia. I've had similar issues with the reversing sensors amonst other things. These problems baffle most engineers and you may end with big bills at the garage, I just pat it on the bonnet and say I understand.

[Zion]

It could be worth doing a BSI reset, if your M59 has a BSI (I think it did by 2010) as all buttons go to the BSI or ECU and they in turn, action the request.

The other thing could be slightly low gas pressure, that can cause the system to stop running, once it had cooled, it works again.

If the condenser pressure gets too high also, during hot weather and there is not sufficient cooling available to bring the pressure down, a pressure switch will trip and stop the compressor from running, but auto-resets once the temperature of the condenser drops - which then allows it to work again.

So check the fan is running when AC is on, and whether the gas needs topped up.