If your air con gas pressure is low the low pressure switch will cut out thus not enabling the air con system to work. Having had mine comprehensively pressure tested, ,oisture removed, re-oiled and re-gassed yesterday by the guys at work whilst I watched it is a mind boggling procedure of gas, pressures, vacuums and the like lolIf you go for a free check ask if you can watch them whilst they work and get them to explain what they are doing.Thats said mine was showing 0.5 bar of pressure, probably never been re-gassed since new. The advantages of having a full dept of instructors in refridgeration next door!!£10 and a packet of biscuits........brrrr it's fritzin in my Ph1 now lol