L3430 AC compressor not kicking in

[WileyG]

This is a well maintained 2004 L3430 HSTC with 1005 hours on it. The screens are clean and the freon is good. Before I start trying to trace wires tomorrow I wanted to ask if there is a relay in the AC circuit that may have died. Over the years since 2016 when I bought it I have had an intermittent problem with the AC not cooling on about 3 occasions but each time I continued to run the tractor and the AC eventually started working. This time, the compressor clutch is not responding at all, no click, no screeching, nothing. The 7.5A fuse is good. A few days ago it did this with my son and he said it finally started working. I wasn't aware of this until yesterday when it didn't work for me and he told me. SO......... any input is appreciated.

 

[diesel85]

Yes it has a relay.

I would test the relay.

It is in the roof of the cab.

 

[Tinhack]

What are the high and low pressures when it's running/not running? What is the ambient temperature when you check? You can't diagnose the AC without knowing that. "Good" doesn't mean anything.

The compressor is typically controlled by the thermostat inside the evaporator case. There may also be a high/low pressure switch. This switch is to save your compressor. Find the connector that powers the compressor and verify the compressor clutch "kicks in" by jumping 12v to that compressor wire. DO NOT leave this wire connected. It's to test the compressor clutch coil only.

 

[WileyG]

What are the high and low pressures when it's running/not running? What is the ambient temperature when you check? You can't diagnose the AC without knowing that. "Good" doesn't mean anything.

The compressor is typically controlled by the thermostat inside the evaporator case. There may also be a high/low pressure switch. This switch is to save your compressor. Find the connector that powers the compressor and verify the compressor clutch "kicks in" by jumping 12v to that compressor wire. DO NOT leave this wire connected. It's to test the compressor clutch coil only.

I don't have gauges to check pressures. The ambient temp was 82 degrees. Since the compressor clutch isn't engaging at all I suspected something electrical....a relay.... I will momentarily jump 12V to it tomorrow to see if it engages and I will also try to track down that relay that diesel85 references.

Thank you both for your input. I need to bush hog 14 acres next weekend and the forecast says 90 degrees so I REALLY need the AC.

 

[Tx Jim]

Due to your statement ""I don't have gauges to check pressures"" what other means are you using besides "guessing" that your tractors AC has correct amount of refrigerant? I suggest for you to have an AC knowledgeable person check your tractor's refrigerant pressures with gauges. If one heater hose don't contain a manual coolant shut off valve I suggest you install a manual shut off valve

 

[5030]

Yes it has a relay.

I would test the relay.

It is in the roof of the cab.

Interestingly, Kubota uses identical relays for everything (under the roof on the left side facing forward) so you can mix and match to see if one is bad. DO NOT buy a replacement relay from your dealer as they charge around 70 bucks for each one and you can get them from Digikey for about 15 bucks each, shipping included. I keep a spare on in the shop all the time, just in case.

 

[5030]

Due to your statement ""I don't have gauges to check pressures"" what other means are you using besides "guessing" that your tractors AC has correct amount of refrigerant? I suggest for you to have an AC knowledgeable person check your tractor's refrigerant pressures with gauges. If one heater hose don't contain a manual coolant shut off valve I suggest you install a manual shut off valve

Jim is stating the best course of action to address the issue. Something that Kubota don't do is install a shutoff valve in either heater hose but is should ne done anyway. Just a tiny amount of bleed past the rotary heater control valve (under the roof) will severely compromise the cooling of the ac in the summer. Put the valve under the hood (bonnet) somewhere convenient. A WOG ball valve is the ticket.

 

[Tx Jim]

Heater coolant line on my '91 JD 4255 has had a manually operated coolant heater hose valve installed since I purchased it used in '93. That valve has remained closed because a tractor heater in Sunny Texas Winter temps is rarely needed but after a few minutes of operation then one needs AC to cool on lower setting

 

[5030]

Without the proper refrigeration tools, diagnosing and fixing any ac (tractor, house or car) is a total crapshoot and stay away from those 'fixes in a can products' as you can overcharge a system and destroy it easily. All refrigeration systems take a very specific amount of refrigerant so guessing don't count and could cost you big bucks in the end.

 

[WileyG]

Tx Jim, I get it that the coolant pressures need to be checked. My intention is to eliminate a lack of voltage or other electrical failure before I get someone else involved OR buy gauges myself. Just the elementary stuff that doesn't cost me anything is what I want to eliminate. AND, I will install a ball valve on one or both heater hoses today.

Thank you all for your input.

 

[5030]

Heater coolant line on my '91 JD 4255 has had a manually operated coolant heater hose valve installed since I purchased it used in '93. That valve has remained closed because a tractor heater in Sunny Texas Winter temps is rarely needed but after a few minutes of operation then one needs AC to cool on lower setting

Opposite here up in Michigan but still have one anyway just because most heater control valves leak. Never could understand why tractor builders don't install them in the first place. Every big I ever drove including the one I own, has heater control valves on the water manifold in addition to the heater mix control valve.

 

[Tx Jim]

134A refrigerant is more intolerant to an overcharge than R12.

 

[Tx Jim]

AC compressor clutch not engaging could be due to refrigerant low or high pressure switches performing the tasks that they were designed to perform

 

[5030]

I did a thread a few years back under Kubota owning and operating, detailing how to insulate the non insulated roof on Kubota tractors. Your blow molded roof is a heat magnet in the sun and really puts a strain on the AC unit trying to cool down the cab. I insulated mine with foil-bubble-foil sheet (available at any box store) and glued it to the underside of the roof with 3M spray on adhesive. Makes a huge difference on a hot sunny day when the sun is beating down on the roof. I've included a picture with the insulation installed.

 

[5030]

Jim... I've switched to dried propane as it's compatible with all modern refrigerants and it provides a much better thermal transfer. Not cheap and hard to find however.

 

[Tx Jim]

Nothing is cheap TODAY due to the China Flu & USA politicians that like to give $$$$$$$$ AWAY. How much does dry propane cost per ounce?

Many yrs ago a local shade tree mechanic was installing regular propane in auto/tractor AC systems. Somehow local law enforcement office got notified of him installing propane in AC systems & told him to cease & desist!

 

[LouNY]

Tx Jim, I get it that the coolant pressures need to be checked. My intention is to eliminate a lack of voltage or other electrical failure before I get someone else involved OR buy gauges myself. Just the elementary stuff that doesn't cost me anything is what I want to eliminate. AND, I will install a ball valve on one or both heater hoses today.

Thank you all for your input.

I would not put valves on both heating lines, you could actually trap pressure in the system or create a vacuum by cooling and heating cycles.
One valve in one line will prevent unintentional heat and not cause any issues.
As far as your cooling, I believe in doing all you can by yourself. However without putting a gauge on the system you are shooting completely blind
you have no idea if the low or high pressure switch is holding you out or the temperature control.

 

[LouNY]

Nothing is cheap TODAY due to the China Flu & USA politicians that like to give $$$$$$$$ AWAY. How much does dry propane cost per ounce?

Many yrs ago a local shade tree mechanic was installing regular propane in auto/tractor AC systems. Somehow local law enforcement office got notified of him installing propane in AC systems & told him to cease & desist!

I would have to wonder under what authority they had to tell him to cease and desist.
Propane is a good effective coolant gas.

 

[Tx Jim]

I would have to wonder under what authority they had to tell him to cease and desist.
Propane is a good effective coolant gas.

You would have to live in my local county to fully understand.

 

[Harry in Ky]

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