# A/C no longer working



## Marty1Mc (Mar 19, 2011)

When you turn on the AC, is the center of the compressor turning? There is a clutch that engages when the AC is engaged. That clutch will spin. If the center is not moving, then next check pressure. If the center is spinning, you still need to check the pressure to make sure you don't have a blockage. But, most likely, it will be simply low on refrigerant. 

What year is your car? If after 1995, it is probably R134A. You may be able to just put a quick charge on it. (R-12 requires a license to buy.) If it's R134A, you can get a refill kit from any auto parts store. Try to find the stuff with dye if possible. Also, make sure it has a pressure gauge on it. The system is filled at the LOW pressure side of the compressor. You can tell the low side by looking at the aluminum piping. The low pressure pipes are larger than the high pressure side. You will find a connector on one of them to allow you to fill the system. 

However, you need to ensure you don't have a major leak. If the pressure is completely gone in the system, then you will need to fix the leak. Once the leak is fixed, it needs to be evacuated. That is sucking out the air (and moisture with it) and creating a near vacuum situation in the system. After that, it can be filled.

Good luck, post back if you have any questions.


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## phantasm72 (Jul 19, 2010)

Marty1Mc said:


> When you turn on the AC, is the center of the compressor turning? There is a clutch that engages when the AC is engaged. That clutch will spin. If the center is not moving, then next check pressure. If the center is spinning, you still need to check the pressure to make sure you don't have a blockage. But, most likely, it will be simply low on refrigerant.


 The compressor does turn, but it goes on and off at about 4 or 5 second intervals. So from what you are saying, it sounds like the pressure is probably very low.
The car is 2001
You were mentioning stuff with a dye? Is that to help locate a leak if there is one?


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## Marty1Mc (Mar 19, 2011)

With the compressor fast cycling, then it's likely low on refrigerant. There is a low cut-off switch on the low pressure line that interrupts the clutch when the pressure drops too low (usually below 20 lbs of pressure). The dye will allow you to use a black light and see where it is leaking. The leak will show up as a bright yellow. 

However, if you can still just use R134A and fill the system. You may find the leak is slow enough that this will work on a once a year basis.


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