Cab air-con was blowing warm air. Unableto reset. Cab air-con was blowing warm air. Unable to reset . ~~~~~ 3512 Cab air-con was blowing warm air Unable to reset.  3512 cab A/c found LP charging nipple leaking. Replaced with a new valve core on the LP charging nipple. Vacuum the system & charged freon. Function check A/c cut-in/out operation - OK. Cab area was cooling & temp. 23*C - 24*C. No other leaks was detected.  Alan/Lee PT/Sarma/Sugu 45033