Will low refrigerant level cause the AC compressor clutch to not engage
Asked by j2sullivan Jul 04, 2014 at 06:31 PM about the 1995 Jeep Grand Cherokee Laredo 4WD
Question type: Maintenance & Repair
Motor running, AC on max, fan on high. Clutch on compressor is not turning. Did not want to charge the system if there is refrigerant at the correct level. Checked the fuse and it is good.
15 Answers
Most of the time this is sign of low freon.
j2sullivan answered 10 years ago
Then it is likely OK to charge the system and then the clutch should engage?
Yes,but i would recommend bleeding it first,to release all air biult up in system.
j2sullivan answered 10 years ago
And the bleeding is done by doing what? Is there a valve to do this? Is it on the low or high side? Or just use the fill assembly with the gauge to bleed? How do you know when there has been sufficient "air" bled off?
j2sullivan answered 10 years ago
Checking in my Haynes manual for the unit does not show or describe any "bleed" operation or screw/valve to use?
ksteinmetz answered 10 years ago
there is no air bleed off valve . when your system doesn't work thenyou should first do what you did and check fuse or electrical issues if thatdoesnt seem to be the problem then you can try to add Freon but your compressor will not engage then there may be other problems. if there is a leak and system is empty comp. will not come on because of low pressure shut off sensor to safe guard your comp. there are really cheap gauges to test pressure but remember to check low side pressure only. if there is a leak it must be fixed and then you must evacuate the system with an vacuum pump to remove water from system must hold at least 30 inches of vacuum at sea level to remove moisture. moisture is ac enemy then when it will hold vacuum for several hours then you know leak is fixed and then you can add froen. there should be no so called air pressure to bleed off. if you do bleed it off it is just money going out as Freon no air. I hope this helps you you can continue to put all the Freon you want into system but it will not work properly until you do it right.
j2sullivan answered 10 years ago
Thank you. Did add the Freon and the AC compressor clutch did engage. It took a while but the level did come up and the cool air did start to blow in passenger area. Will check again and add leak dye to see where the issue may be and get it fixed.
ksteinmetz answered 10 years ago
i am glad i could assist somewhat. my info is a little jumbled but glad i could help.
Any ideas on why my a/c system would loose gas after the radiator fan getting damaged? Prior to this a/c was in good working condition. Thank you
AutoPartKid answered 8 years ago
If the fan is not working properly it gets really hot and will not work properly the fan should always be in good working condition in order for the AC work good .
ac on max..everything fine....car heats up and clutch do no engage..to keep car cool...next day ..same thing....ac on max....suddenly car heats up....clutch not engaged...what is my problem....I checked the fuse on side of dash board....1998 ford ranger xlt..
Le_Prasson answered 5 years ago
Hello, Could low refrigerant cause fans not to run? the only time fans fun is when the engine is hot. It does not run for any A/C setting. Thank you
I pulled vacuum and needed ac to pull in the correct amount of refrigerant in. I did this and it charged up immediately. Its a way to force the compressor to turn on and transfer to the high side. Jump pins 30 to 87. Pins 85 and 86 on relay are what triggers the jump electrically with a ground and a 12 volt. I replaced relay after doing this and it engages on its own now. No harm done if you do this while you have refrigerant going into only the low-side.
Make sure to not jump pins 85 and 86, this will blow a fuse. You can find the clutch relay in fuse box and do it there, on mine the two contacts to jump where copper on the relay and had slightly bigger legs the two other ones were the triggers.you can test this by using a meter to find the pin with constant which is usually 30. Pin 87 is what pin 30 connects to when the ac actually kicks on. Just trying to extra clear, sorry for repeated info but just trying to help others. The fan kicked on when high side pressure went up like its designed to do and the high side pressure went down while i was charging. Pressure never exceeded 200 psi. The Haynes manual suggested 160 to 210, low side never exceeded 60 psi and would go down and back up when ac pulled into high side. Since I weighed the exact freon I added I knew I would be under the maximums for both high and low. one 12 oz can and 10 more oz by measuring with a scale tared it and stopped at -10 oz. the gauges showed proper low side and high side for the ambient temperature outside. Make sure to replace relay after. Oil should still remain in system if compressor is not replaced. You can see how many lbs of r134a it requires. Mine required 1.1 to 1.4. I added 20 oz or 1.25 lbs. had ice cold ac. I only replaced one hose that was leaking and pulled vaccuum after to evacuate air and let the vaccuum add 40 psi of charge to lowside. I found this out due to trial and error and never could get ac to kick on even though the light said its on.
By replace relay I mean the same one. You dont need to buy a new one as it should engage on its own after the car seeing proper pressures and knows the compressor can actually turn on on its own.
