TC reported air-con fault at rear M2 car#2 set. Unable to reset. Staff (CTH) checked and confirmed that car 2566 air-con was working. Car was cooling. ~~~~~ 2566 TC reported A/C 2 fault Unable to reset. Staff(CTH) confirmed 2566 air-con was working. Car was cooling. CE reported car 2566 A/C 1-2 fault,but cooling ok.  2566 A/c 1-2 found liquid line connector seepage & tightened connector. Discharge/vacuum/charge 6.8kg of 407C freon. Function check & no A/c fault found. Saloon temp. 24'C.  Chan SW/Hanafi 44193