When you are having a cooling problem with your cars air conditioner the most likely cause is low refrigerant in the system. This means there is a leak in you’re A/C system and the refrigerant has escaped from a bad O-ring, leaky compressor, faulty hose or a small hole in the condenser or evaporator. The leak will need to be repaired before the system can be recharged. On most compressors there is a low pressure safety switch that will detect if the system is low on refrigerant and prevent the compressor clutch from engaging.
The next thing that should be checked is to see if the compressor is engaging. If the compressors magnetic clutch does not engage when the air conditioner is turned on, then you could have a wiring problem or a blown fuse. If it turns out to be a blown fuse, replacing the fuse could be a temporary fix. You need to find out why the fuse blew in the first place and correct the problem so it does not happen again. If the compressor is receiving voltage but not engaging then the clutch is bad and will need to be replaced. If your compressor is not turning, then it has seized up and will need to be replaced. Most compressor failures are caused by loss of lubrication, a blockage in the system or using the incorrect lubricant.