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Recharge of ac

2000 Jeep Grand Cherokee with 134000 miles, ac has started to act up. Picked up a kit to recharge the system, with the gauge on the low pressure side, the needle is buried. I expected to see a low reading, ac was running on high. Could it be the compressor is not working? How can you tell if the compressor is running properly? Thanks for any input.

Look at the front of the compressor. If the compressor isn’t operating the clutch plate at the front of compressor belt will be stationary while the belt is spinning around the compressor pulley.

If the gauge on the recharge kit reads zero, the system has been open to atmosphere, and a simple recharge kit isn’t going to fix the AC system.


you will need an a/c shop need to suck the system down with a vacuem pump and make sure it holds the vac. then you can recharge the system. if it dos’t hold vac need to find out way then repair the system.

Well Tester, it seems to be the compressor, the front of the clutch plate will spin by hand but does not engage when the ac is turned on…

The compressor clutch is activated with an electric current (solenoid).
You need to see if the clutch is getting power and engages.
Look for a single thin wire going to the front of the compressor.
Check with a meter or test light if it’s getting 12V when the AC is on.

If there’s no voltage there’s an electrical problem elsewhere, assuming there’s enough gas pressure to close the low limit switch.
You can take a wire (preferably with a ~10 amp fuse in line)
and run it from 12V to the clutch and see if it engages.

If there is voltage either the clutch or the electrical connector on it is bad.

It may be possible to replace the clutch without replacing the compressor or opening the refrigerant system.

If the pressure in the system is too low, a limit switch prevents the compressor from engaging and destroying itself trying to operate an empty or near empty system…Is your pressure gauge reading zero or is it reading maximum ?? If its reading high-pressure, the system (compressor) should at least kick in for a few seconds when you turn it on…if not, check the switch, fuse, relay that controls the compressor…

There is a relay in the circuit for the compressor clutch and its a common problem on this vehicle. This vehicle with a bad relay was used on a national TV news show where they went to several garages to see how many would find this and fix it for a fair price. Hidden camera under the hood and all that.