Climate compressor no longer starts (Volvo V50 2.0d)

Hello together, maybe you have an idea. So: – Air conditioning didn’t work anymore (compressor no longer starts) – Then re-fill the system (according to the workshop hardly anything was missing in air conditioning fluid) – Unfortunately without success – All fuses checked (but nothing broke) – The system was tested for leak (condenser not defective) Workshop suspects that the turn-on electronics is defective, since the signal is not “ON” when pressing the A/C switch in Vida Only when the switch is held down, then time the parameter “ON” on. Workshop now wants to exchange the electronics on suspicion (cost point still unknown)? Does anyone have an idea? Would be very grateful for every tip.