A/C problem

[Mildthunder]

Hi everyone. My first post here.

Have a 2016 5085E . Recently, the A/C started not cooling. I noticed the compressor clutch is rapidly cycling on and off. At first I thought low charge, but thats not it. The clutch engages and disengages very fast. Like engage for 1 second, disengage for 1 second, repeat. It seems to only do this when its above 85* ambient. Cab filters cleaned and replaced, condenser filter cleaned, all good there.

Any thoughts?

 

[TractorGuy]

Low charge or failing low pressure switch. Have you connected a set of gauges to it?

 

[Mildthunder]

I only had my low psi side gauge , it was showing 45psi compressor on, but once clutch starts going crazy so does the gauge. Sometimes it works fine and the clutch cycles normally and air blows ice cold.

 

[rustyshakelford]

Check for faulty clutch wiring

Brett

 

[TractorGuy]

Try bypassing the low pressure switch with both low and high side gauges connected. You need to keep the clutch engaged with both gauges for starters.

 

[Tx Jim]

I only had my low psi side gauge , it was showing 45psi compressor on, but once clutch starts going crazy so does the gauge. Sometimes it works fine and the clutch cycles normally and air blows ice cold.

One can't diagnose AC problems successfully without utilizing both high & low pressure gauges.

 

[R134a]

Mobile A/C is charged by weight, not pressure.* ....Because weight is a constant. Once you have the correct charge then a set of guages can be used to detect problems. Speculation..... (Rapid cycling is textbook low charge.) You ruled that out how? :confused3:

 

[Tx Jim]

R134A
It difficult for the average shade tree mechanic to measure the refrigerant out in a hay field BUT I've been successful getting my AC systems blowing "cold air" by watching the pressures on both gauges. It may not be correct but it sure beats paying 100's of $$$ for service call/labor & waiting on technician to arrive to measure oz's of refrigerant.

 

[R134a]

I get it. I don't want him to make a mistake and wind up with an expensive headache. He is welcomed to call me & I can walk him through it.

 

[Harry in Ky]

Mobile A/C is charged by weight, not pressure.* ....Because weight is a constant. Once you have the correct charge then a set of guages can be used to detect problems. Speculation..... (Rapid cycling is textbook low charge.) You ruled that out how? :confused3:

Yes, weight may be a constant in the academic sense, but in the field it's a different story. If every system's refrigerant weight REMAINED constant, there would be far fewer problems and much less need for people to work on them. Charging strictly by weight is great in theory, but not always practical in practice.
While I personally have serviced/charged multiple hundreds of tractor A/C systems over the years, both R12 and 134A, I can assure you that the factory recommended "charge weight" spec is NOT always readily available. Even if it were, how does one translate that in a partially charged system as is most commonly found in most cases when a person says his A/C isn't cooling and it's up to you to make it work?
Yes, sometimes mistakes can be costly, but ask a man who's been sweating in a glass box all day if he's willing to "chance" a mistake by someone with a set of gauges, a jug of freon, and a reasonable amount of experience over waiting for someone else to come along who knows all the "theories".