Why does my AC pump turns on and off in my 2011 John Deere 85D, cooling not satisfactory.

[Serega]

Any one knows why does my AC pump comes on and off every 10-20 seconds or so regardless of what ac setting I have it on (even on coldest setting) resulting in not so cold air inside the cab? (2011 John Deere 85D)

After the AC is turned on, right away the relay would click and the pump would engage and the cooler air could be felt, however after about 15-20 seconds the relay would click again and the pump would disengage resulting in produced air at the vents warming up, and then after about the same time it would click and engage again and it would continue operating that way. I have recharged the ac system with one of those automotive DIY recharge kits as the pressure was on the lower side, and that resulted with much colder air when the pump is on, however the whole on/off sequence is still going on which results in not very comfortable temp inside on a hot day (well, it was not cold enough on a 87* day, so I can't imagine a 90* + weather)

Is this normal operation for the AC pump, maybe to conserve fuel or something or is there something wrong with the system? Also, is it a good idea to just bypass the relay that does that?

Any advice is appreciated.
Thanks in advance.

 

[heymccall]

The compressed gas in the system has had some leak out. The system should be checked for leaks and topped off to the correct amount.
The system is under charged and the cycling is due to insufficient refrigerant.

You says you added refrigerant. By what means did you determine how much to add?

 

[mg2361]

Check your filters. Also need to check the AC charge with gauges or an AC machine. Is the evaporator freezing up?

 

[Serega]

The compressed gas in the system has had some leak out. The system should be checked for leaks and topped off to the correct amount.
The system is under charged and the cycling is due to insufficient refrigerant.

You says you added refrigerant. By what means did you determine how much to add?

Buy following the instructions and the pressure gage on the ac recharge kit/container..

 

[Serega]

Check your filters. Also need to check the AC charge with gauges or an AC machine. Is the evaporator freezing up?

filters are clean/new. I haven't been checking the evaporator but would I freeze in like 15 seconds? I'll have to check that..

 

[BigWrench55]

Couple things that will cause your compressor to cycle on and off. One is that you are low on freon. The other is that you have debris in the expansion valve causing the low side to pull a vacuum . Throw away the autozone freon charge kit and get yourself a set of gauges and a few cans of freon. I prefer to have a 30lb jug of freon. But if you only have one thing with a/c then cans will do. A/C gauges will tell you everything that is wrong with your system. You need to see what the low and high side of the system is doing to know what your problem is. I never concern myself with capacities just what the pressures read. Depending on ambient temperatures is what your pressures will read. You can find pressure temperature charts on the internet. Good luck to you.

 

[92U 3406]

Agree with everything above. Gauges are the tool you need to test this. Run the system with gauges on it and report back with some pressures and we'll be able to provide some more feedback.

 

[Serega]

Couple things that will cause your compressor to cycle on and off. One is that you are low on freon. The other is that you have debris in the expansion valve causing the low side to pull a vacuum . Throw away the autozone freon charge kit and get yourself a set of gauges and a few cans of freon. I prefer to have a 30lb jug of freon. But if you only have one thing with a/c then cans will do. A/C gauges will tell you everything that is wrong with your system. You need to see what the low and high side of the system is doing to know what your problem is. I never concern myself with capacities just what the pressures read. Depending on ambient temperatures is what your pressures will read. You can find pressure temperature charts on the internet. Good luck to you.

thanks Paul. I might just have to do that, or may be hire someone who does this for a living..