AC keeps blowing fuses

Jbeerman9

New member

Equipment
Kubota L3430
May 31, 2022
6
1
3
Marquette,Michigan
hey guys…I have an L3430. Only 660 hours. Just bought it. Like an idiot I didn’t even think of checking the AC operation since it wasn’t that warm when I picked it up and due to the low hours and great condition of the tractor. Well, low and behold I turn on the AC and it keeps popping fuses but only when AC is on. I’m pretty mechanically inclined but will say AC/electrical issues are not my specialty. I see the previous owner must’ve not had proper belt tension and it rode over the compressor clutch and wore through the clutch wiring connector. Not to the point of severing the connections but bad enough I had to remove the wires and connect them separately to the clutch connection. Made no difference. Bought a compressor clutch, no difference. Charged system with both old and new clutches, same fuse popping issues. I’m stumped…..any ideas guys ?
 

jkrubi12

Active member

Equipment
B2601HSD, LA435/QA 54, LP SGC0554, LP BB1254
Sep 24, 2012
119
107
43
right coast
First, the problem may have existed prior to your ownership. Ensure that the fuse(s) that are 'blowing' are of the proper rating for the load, should be info in owner's manual for that. They could have been replaced with whatever was on hand by the prior owner.

If the previous owner experienced the belt tension issue (causing damage) that may have been incorrectly repaired. Try to obtain info on those components and ensure that any repairs were completed properly. Could be a misconnected wire in there somewhere, or some mysterious ground-short. ,

Do you experience any other electrical-related issues, especially when using any other electrical systems? If so, they could be a clue to the underlying problem and may let you find the solution easier.

I'm thinking that the damage and subsequent repair is the source of the problem. It could be that poor wiring technique (causing a marginal connection) results in an over-amperage draw when initiating the AC.

That's all I can scrape off my brain for now, good luck! You'll need it with electrical gremlins! :cry:
 
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Jbeerman9

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Equipment
Kubota L3430
May 31, 2022
6
1
3
Marquette,Michigan
First, the problem may have existed prior to your ownership. Ensure that the fuse(s) that are 'blowing' are of the proper rating for the load, should be info in owner's manual for that. They could have been replaced with whatever was on hand by the prior owner.

If the previous owner experienced the belt tension issue (causing damage) that may have been incorrectly repaired. Try to obtain info on those components and ensure that any repairs were completed properly. Could be a misconnected wire in there somewhere, or some mysterious ground-short. ,

Do you experience any other electrical-related issues, especially when using any other electrical systems? If so, they could be a clue to the underlying problem and may let you find the solution easier.

I'm thinking that the damage and subsequent repair is the source of the problem. It could be that poor wiring technique (causing a marginal connection) results in an over-amperage draw when initiating the AC.

That's all I can scrape off my brain for now, good luck! You'll need it with electrical gremlins! :cry:
Thank you for the reply. I’m sure the problem existed prior to me buying it. So it is nothing I did.

All other electrical is in proper working order. The 7.5 amp fuse is the correct fuse. It’ll blow a 5, 7.5, 10, 15, etc.

The funny thing is it’ll work for like 2-3 minutes and then pop the fuse. Did I mention how I hate electrical issues. I’m probably overlooking something simple but who knows. Good thing summer only lasts three months here in the U.P. of Michigan and then requires heat instead, lol.

Hopefully some others will chime in….
 
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Mark_BX25D

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Bx25D
Jul 19, 2020
784
471
63
Virginia
All other electrical is in proper working order. The 7.5 amp fuse is the correct fuse. It’ll blow a 5, 7.5, 10, 15, etc.
Don't EVER replace a fuse with a larger fuse! That's how wires and components get melted, and worst case, how fires start.

It's NEVER the right thing to do.


The funny thing is it’ll work for like 2-3 minutes and then pop the fuse.

Hmm. I'm wondering if the compressor itself was damaged mechanically when he had the belt too tight. Run it a bit, it gets warm and starts heating up and drawing more current....


But since you know of prior damage to the wiring, I suggest looking there first to make sure the repair was done correctly and nothing was overlooked. It's easy to miss something.

Quick tip for troubleshooting while blowing fuse so you don't have to burn through a 100 pack while troubleshooting: Make up a test light. You want a standard 12v bulb (not LED) and an inline fuse holder isn't a bad idea. On this fuse, you CAN go big - say 30 amps. THe test light is going to limit the current flow.

You'll need a standard 12v bulb socket with pigtails. Pick one up at any parts store, along with a couple of bulbs to fit it. Like this:


Then splice in an inline fuse holder.

Now on the ends you need a couple of male quick disconnects. The most common size is .250, but if you can find some .177s it will work better. OR just use some side-cutters and trim the .250s down to fit.


What you are making is a test light that can plug into the fuse socket in place of the fuse. Now, when there is current flowing, you'll be lighting a light bulb instead of blowing a fuse.

Now test away to your heart's content while NOT blowing through a mountain of fuses.
 
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GeoHorn

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I can strongly suggest that you Stop installing larger and larger fuses…unless you wish to see your tractor burn up in a fire. Whatever is causing the electrical-short and “blowing” the fuses is being overheated over and over and over again….every time you replace that fuse…. and using larger amperage fuses than the design calls for creates even more heat.

Do you know how to use a VOM (volt/ohm-meter)? If so, … then leave the AC switch OFF. Disconnect the clutch. Set the VOM to “ohms”… and start testing each wire in the circuit to discover which of them is “grounded”. While all “grounds” are not necessarily defects….. it’s highly likely one of them is.

(I posted this and then realized Mark and I were posting simultaneously…. and I wish to point out that the only thing electrical on the compressor is the clutch. A damaged compressor will not blow a fuse.…so I highly doubt that is the electrical issue.)

Question: Does the cabin fan operate at proper speeds?
 
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jkrubi12

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B2601HSD, LA435/QA 54, LP SGC0554, LP BB1254
Sep 24, 2012
119
107
43
right coast
After reading the last two replies, I'm in agreement w/Mark_BX25D in his comments about the compressor being damaged.

If the system runs normally at first, then blows the fuse, the amperage is increasing for some unseen reason. The scenario described by Mark_BX25D seems plausible. Somehow, the compressor/clutch assembly seems to be drawing more amps as it heats up. Not being an AC tech, and having zero experience with a Kubota AC system, the evidence at hand leads me in this direction. Good luck!(y)
 
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woodman55

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L6060HSTC, RTV 1100
May 15, 2022
265
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canada
Leave the clutch unplugged and try it. That will tell you whether it is clutch or tractor/harness related.
 
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hagrid

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K1600GTL, ZX-14R
Jun 11, 2018
447
348
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Pittsburgh
I see the previous owner must’ve not had proper belt tension and it rode over the compressor clutch and wore through the clutch wiring connector. Not to the point of severing the connections but bad enough I had to remove the wires and connect them separately to the clutch connection.
Pictures, plz.
 

GeoHorn

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After reading the last two replies, I'm in agreement w/Mark_BX25D in his comments about the compressor being damaged.

If the system runs normally at first, then blows the fuse, the amperage is increasing for some unseen reason. The scenario described by Mark_BX25D seems plausible. Somehow, the compressor/clutch assembly seems to be drawing more amps as it heats up. Not being an AC tech, and having zero experience with a Kubota AC system, the evidence at hand leads me in this direction. Good luck!(y)
The clutch is only an electro-magnet. If the new clutch were the problem then he could turn the AC “on” with the engine NOT running and the fuse would still “blow”…. however…. even brand new equipment can be in failure-mode and, while unlikey, the new clutch may be drawing too much current. (AC clutches are activated by passing current thru the electro-magnet coils then to ground. A shorted coil would blow a fuse and a new clutch with a new coil may have a mfr’g defect. .. Unlikely, but possible.)

@ the OP: When you say you replaced the clutch: Did you actually install a NEW clutch?… complete with a NEW coil..??
 

BAP

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2012 Kubota 2920, 60MMM, FEL, BH65 48" Bush Hog, 60"Backblade, B2782B Snowblower
Dec 31, 2012
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New Hampshire
Your power issue can be anywhere between the switch down to the AC clutch. Possibly you have a short in the cab or somewhere else in the wiring harness. Unlikely that a damaged compressor would cause the fuse to blow because there is no power feeding it. Only the clutch has power. A damaged compressor will either chew the belt up or throw it off or just not work.
 
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Jbeerman9

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Equipment
Kubota L3430
May 31, 2022
6
1
3
Marquette,Michigan
I can strongly suggest that you Stop installing larger and larger fuses…unless you wish to see your tractor burn up in a fire. Whatever is causing the electrical-short and “blowing” the fuses is being overheated over and over and over again….every time you replace that fuse…. and using larger amperage fuses than the design calls for creates even more heat.

Do you know how to use a VOM (volt/ohm-meter)? If so, … then leave the AC switch OFF. Disconnect the clutch. Set the VOM to “ohms”… and start testing each wire in the circuit to discover which of them is “grounded”. While all “grounds” are not necessarily defects….. it’s highly likely one of them is.

(I posted this and then realized Mark and I were posting simultaneously…. and I wish to point out that the only thing electrical on the compressor is the clutch. A damaged compressor will not blow a fuse.…so I highly doubt that is the electrical issue.)

Question: Does the cabin fan operate at proper speeds?
cabin fan operates as it should
 

Jbeerman9

New member

Equipment
Kubota L3430
May 31, 2022
6
1
3
Marquette,Michigan
The clutch is only an electro-magnet. If the new clutch were the problem then he could turn the AC “on” with the engine NOT running and the fuse would still “blow”…. however…. even brand new equipment can be in failure-mode and, while unlikey, the new clutch may be drawing too much current. (AC clutches are activated by passing current thru the electro-magnet coils then to ground. A shorted coil would blow a fuse and a new clutch with a new coil may have a mfr’g defect. .. Unlikely, but possible.)

@ the OP: When you say you replaced the clutch: Did you actually install a NEW clutch?… complete with a NEW coil..??
yep, new complete clutch with coil
 

Jbeerman9

New member

Equipment
Kubota L3430
May 31, 2022
6
1
3
Marquette,Michigan
Well, I’m embarrassed to say I didn’t look close enough at the fins in the condenser. They were PACKED with dirt and debris toward the backside where I didn’t really look hard enough. 15 min of blowing it clean along with the radiator and now it works and doesn’t blow the fuse. Doesn’t seem as cold as it should but will suffice for now.

Update: after 20 minutes of running, the AC is warm. Guessing compressor is shot. Tuesday’s project once the filter drier arrives.

Manifold reads 60 low side and 100-125 high side which I know isn’t right. I’ll try and attach a video if it will let me here. Clutch engages for 2-5 seconds, then disengages for same amount of time then was engaging for a solid few minutes and then back to short intervals again.
 
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GeoHorn

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Well, I’m embarrassed to say I didn’t look close enough at the fins in the condenser. They were PACKED with dirt and debris toward the backside where I didn’t really look hard enough. 15 min of blowing it clean along with the radiator and now it works and doesn’t blow the fuse. Doesn’t seem as cold as it should but will suffice for now.

Update: after 20 minutes of running, the AC is warm. Guessing compressor is shot. Tuesday’s project once the filter drier arrives.

Manifold reads 60 low side and 100-125 high side which I know isn’t right. I’ll try and attach a video if it will let me here. Clutch engages for 2-5 seconds, then disengages for same amount of time then was engaging for a solid few minutes and then back to short intervals again.
This might be due to low refrigerant level.
 
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Flintknapper

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L2350DT
May 3, 2022
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Deep East Texas
Manifold reads 60 low side and 100-125 high side which I know isn’t right. Clutch engages for 2-5 seconds, then disengages for same amount of time then was engaging for a solid few minutes and then back to short intervals again.
Compressor should not 'short cycle' that often and your high and low side readings suggest possibly being undercharged with refrigerant.
 
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lugbolt

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ZG127S-54
Oct 15, 2015
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normally a failed compressor won't cause the clutch circuit to become overloaded and "pop" the fuse.

The clutch only draws so much amperage regardless of how much mechanical load is placed on the clutch. If the compressor is bad, generally speaking one of a few things will happen. One, it'll seize and smoke the belt. Two, the a/c won't work. And three, the entire system will be full of failed compressor material, negating a complete system replacement in order to do the job correctly so that it will last. Otherwise you're taking a chance of repeating replacement of expensive components.

IIRC your tractor uses a scroll-type compressor. Very efficient design. BUT they are not bulletproof. If anything they're slightly more sensitive to moisture in the system and high temp and pressure. So, if the screen and/or condenser are run for a long time being plugged with chaff, the compressor will run hotter than it's designed to, as well as higher pressure than it's designed to, and over time will eat itself.

Anyway back to the topic of blowed fuses. Yeah I'm from the South, I say "blowed". The fuse is seeing excessive amp draw through it's circuit, which causes the element inside the fuse to melt. But therein lies the question why is it getting so much current through it? You have stated that it will run a while before it pops the fuse, that tells me that the liklihood of a shorted circuit is low. Thus, the next most plausible theory would be that of a component or conductor that is either (1) intermittently shorting to ground (or Kubota calls it "earth") or (2) a component or conductor is corroded, or whatever, causing higher resistance, leading to an overheated circuit.

So what I would do in a situation such as this is to grab your wsm, and look at the a/c circuit. Find the fuse in the wiring diagram and follow where the wires go. One side will end up at battery voltage. The other end, however, may feed the fan, compressor clutch, switch, whatever. Every one of those components in the fused circuit are then a potential culprit.

I find it best to grab a piece of paper, and write down the possibilities, then eliminate them via testing one by one, and don't forget to test the conductors (wires) as well. At some point you will figure it out.
 
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jkrubi12

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B2601HSD, LA435/QA 54, LP SGC0554, LP BB1254
Sep 24, 2012
119
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right coast
Sure sounds like you've discovered the underlying problem (y) so now for the fix.

Personally, in your case I would take the chance of re-charging the AC system (don't forget to replace the pressure valves to prevent freon leakage or you'll be back to square one) before I started a compressor replacement job. But let others with more experience chime in before deciding.

Just think: when your'e done with this fix you will probably be somewhat of a 'subject matter expert' on Kubota AC diagnosis & fix! :ROFLMAO:
 
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GreensvilleJay

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BX23-S
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re:
Clutch engages for 2-5 seconds, then disengages for same amount of time then was engaging for a solid few minutes and then back to short intervals again.

this:...'might' be normal if there's a 'computer' controlling the clutch power. Modern A/C systems 'cycle' the clutch/pump on-off as an energy saving method and to better control the 'temperature in the cab'. I know my '97 F150 does this, as does the house A/C unit.

still mulling over the blowing of the clutch fuse though. E=PTO units in riding mowers are about 3 ohms, so they draw 4 amps,and will work 'forever', unless you don't secure them and they spin round and round stripping the wires and blowing the main fuse buried in the back of the rider......
I'm thinking in your case that fuse also powers something else than just the clutch.
 

GeoHorn

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Low refrigerant
 
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