tama, ibalik sa dating set-up ang ac mo (esp kung ATC). have it checked by qualified tech or sa casa. the ac system is controlled by computer, the computer must know that you want the ac on para ma adjust nya and engine speed mo before turning on the compressor. when operating at wot (wide open throttle. the computer will automatically cut the compressor operations), also pag mataas head pressure i cut din ng computer ang ac. yung icing ay madaming pwedeng maging cause; pwede ding sira ang low pressure cut-off switch, undercharge, madumi,wiring papuntang ac relay, etc.