回複：大熱天的，車子的空調S啦！ 急、、、

check the following:
when u turn the ac on/off, blower on, the AC clutch will engage/disengage. If not, there could be a bad switch, fuse, relay, or low on 134a (newer cars).Check all these out if u have a repair manual or handy.best way to check if a compressor is not the problem is hard wire it from the battery.
U'll need a pressure gauge to check the pressure if the AC clutch can engage but stop engaging after a while. it is likely low on refrigerant and if u did not have this problem before, there is likely a leak in the system needed to be found and fixed.
If u don't know anything about the stuff above, u r probably better off to have it checked by a shop.
Good luck