TC reported cab air-con faulty. Unable to reset. Cab very warm. TC reported cab air-con faulty. Unab le to reset. Cab very warm. ~~~~~ 3682 (W) TC reported cab air-con faulty Unable to reset. Cab very warm.  3682 Measured Cab aircon freon LP 50psi, HP 0. Discharged freon & vacuum. Charge freon to LP 68psi, HP 240psi. Monitor for 3 hrs, no drop of freon pressure. Changeout cab filter as preventive measure.  Aliff/Daniel/Chan SW 45463