Technical A/C control switch

[Tenor]

Hello all.
My 2008 Ducato Motorhome has cab a/c but the a/c button on the heater control panel (see image) is not working. Is it possible to service or change the control button and switch, or does the whole heater control panel need to be replaced? There is plenty of gas charge in the system but no electrical connection to the actual ac motor.
Tenor

 

[Communicator]

Unless the design of the control was changed significantly from my earlier x244 model, then replacement, if necessary, should be possible. Access is from the top, by removing radio and holder, but others have suggested working from the side with the lower dash removed. I do not know whether that approach is viable.