When you switch on the AC, the clutch attached to the pulley on the compressor should engage. Looking at the face of the compressor, the clutch appears as a plate on the front of the pulley. With the AC off, the clutch does not spin.
If the center of your a/c compressor is turning while the engine is running then it is engaged! You will also hear a definite click when you press the a/c button and if your compressor is working well you should see a definite drop in rpm when engine is idling and you switch on your a/c. About 50 rpm.
As far as the fan running but not the compressor, that is absolutely possible. Usually when that happens it is caused by one of two things, a bad capacitor or a bad contactor. The capacitor gives the unit extra power needed when starting. It may have more than one capacitor.
Take the fused jumper wire and connect its one end to that side of the wire connector that was connected to the compressor. Attach the other end of the jumper wire to the positive terminal of the battery. It will supply the battery voltage to the compressor clutch, allowing it to engage manually.
In conclusion, when an AC compressor is not kicking on, it can be caused by a variety of factors, ranging from low refrigerant levels to faulty wiring or a damaged compressor.
If the AC compressor is not working but the fan is running, check to see if it is blowing warm air instead of cold. If so, it could be the valves. When the valves are broken, they don't allow the refrigerant to do its job. As a result, the liquid doesn't convert to gas when it reaches the compressor.
Most air conditioners come with a reset button attached to the compressor unit. Typically, it is a red button and is very visible to an onlooker. To reset your air conditioner, all you have to do is press the button, and you won't have to worry about all the heavy lifting.
Place the red pin on C and the black pin on S. Place the pins on the black and red wire from your multimeter onto the terminals. Once you place the pins on the terminals, your multimeter should have an ohm reading of less than 30. Anything significantly above this reading indicates that your compressor may be broken.
If the refrigeration circuit seems to be working (refrigerant in the system, compressor running and building pressure), but there is still no cooling, the problem might be an obstruction in the orifice tube (located in the high-pressure hose between the condenser in the front of the radiator, and the evaporator located ...
Squeals are standard when starting your air conditioner and aren't signs of an issue. However, if the squealing AC compressor noise lasts longer than 10 seconds, it could be a symptom of a severe problem.
If your old AC compressor still has a valid warranty, you might spend between $600 to $1,200 under warranty, but if the compressor you're replacing has an expired warranty, expect to pay closer to $1,300 to $2,500.
Instructions for Operating an Air Compressor
Attach the air hose to the hose connector. Then, close the regulator knob and ball valve. Once plugged in, turn the power switch on. Wait until the compressor's motor shuts off before using it.
The location of the reset button on your compressor can vary depending on the model and manufacturer. Typically, it is located on the motor or near the motor housing. Look for a small red or black button that is often labeled “reset.”
The main reasons your AC unit outside is not turning on could be something that has tripped the circuit breaker, something is blocking the fan's airflow, or the condensing unit is damaged. Other potential issues could be the thermostat isn't set correctly or the compressor could be malfunctioning.
If the compressor is not working, the fan will not be able to do its job properly and cool air will not be circulated. In some cases, the AC fan may still run even if the compressor is bad, but it will not be as effective in cooling your home.
You'll want to have the unit examined for signs of a blown fuse, tripped circuit breaker, broken thermostat, or dirty air filters. Dirty or clogged filters commonly make AC compressors stop working. When it comes to operating your cooling system properly, be realistic with the temperature setting on your thermostat.
One of the reasons why compressors do not engage is because of a low pressure lockout, a poor ground, a bad clutch coil, an opening in the wire to the clutch coil, or simply a blown fuse.
One easy way to tell whether the compressor is seized is to try to turn the compressor clutch, which is attached to the compressor shaft, by hand (you do NOT need to remove the drive belt to do this). If the compressor is hard to turn or does not turn at all, the compressor has failed internally.