AC compressors not coming on

My A/C compressors is not coming on when A/C is activated or in De-frost mode. I've check all fuses and relay's. Someone suggested that it maybe the magnet inside the compressor that is shot?!?!?!

Have you checked to see if there is R-12 or 134A at high enough pressure. If the coolant is low or gone, the compressor should not come on or it would burn it up. I doubt the magnet is dead because it should be an electromagnet. If there is current it should pop in gear. The clutch could also be worn out.

Disconnect the pressure cycling switch on the accumulator. Jumper a wire across the electrical connector. If the compressor comes on, then it could be:

1) not enough r12/r134a
2) the pressure cycling switch is bad

Before adding r12/r134a check the pressure on the low side. If it is below 25 psi for r12 or 21 for r134a, then you are low on freon.

If the pressure is higher, the switch is probably bad.

//2000CAYukon

Disconnect the pressure cycling switch on the accumulator. Jumper a wire across the electrical connector. If the compressor comes on, then it could be:

1) not enough r12/r134a
2) the pressure cycling switch is bad

Before adding r12/r134a check the pressure on the low side. If it is below 25 psi for r12 or 21 for r134a, then you are low on freon.

If the pressure is higher, the switch is probably bad.

//2000CAYukon


dont forget to purge your lines:)

There is a leak somewhere and the only way to find the leak is putting leak dye in.It will be easier to find the leak with a special light.The price of R134A has gone up because some of the manufaturers of R134A are supplying to the automakers only.

There is a leak somewhere and the only way to find the leak is putting leak dye in.It will be easier to find the leak with a special light.The price of R134A has gone up because some of the manufaturers of R134A are supplying to the automakers only.


I might be wrong but you can also try using nitrogen just be sure not pressuerize over the max pressure of the evaporator then use a bubble solution to find a leak before that look at your guage pressure and see if its holding if it is then you dont have a leak