M59 Help: Dealer Wants $6K to Replace the Wiring Harness

[TheParkRanger]

Kubota M59, unknown year, ~2600 hours. I've had it about 10 months, have close to $40K into it including major service, new brakes, and completely rebuilt loader and loader hydraulics. I just point this out to say I've been operating with an open checkbook to get this puppy sorted, but I'm pretty sure the dealer is tired of fussing with it and finally gave me a go-away quote regarding this electrical gremlin I've been chasing.

Unfortunately, tractor has been more down than up. I'm the official-unofficial mechanic here at a tropical fruit park under construction in Central Florida. Primary duties for this bad boy are moving mulch, logs, and general sitework. We're blessed to have it, but electrical issues have hobbled it a lot.

TL;DR - Machine keeps blowing:
- the (#7) 5amp fuse for the "brake lamp switch" (orange, 2nd from top right)
- the 30amp slow-blow "keystop" (pink, 2nd from left)

Despite their labeling, one or both of them are involved with the start sequence, specifically the fuel shutoff solenoid (which I have replaced).

Trouble Sequence: No Start
- When turning the key to the 2nd position (before start) — the operator is supposed to hear to the fuel shutoff solenoid open (it does not)
- Then as soon as I depress the clutch pedal (again, before start), the #7 5amp will blow

- The 30amp slowblow gives me trouble in fits, I can't replicate a specific sequence before it

Attempted Remedies
- (3) trips to the dealer where they replaced the fuses, drove it around a little bit, sent it home to me, had the fuses continually blow again 1-3hrs back into operation
- 4-5 hours (from me) looking for any broken wires that I could see in these circuit(s), replacing, repairing, and protecting them ( I can solder pretty alright)

Would be looking for any and all help — including moral support — in chasing down these electrical gremlins, suggestions for things to do beyond above, tips for finding breaks I can't easily see, or ideas on how to bypass some of the circuit to help troubleshoot. I have a multi-meter but I'm not super great with it, for example, I'm not even sure if a fuse is blowing if that intones a problem upstream or downstream of the fuse, or if it could be both.

Thanks in advance. I need you guys.

 

[KWentling]

You are only looking down stream (load side) of the fuse. A good method for finding shorts is to substitute a test light in place of the fuse, and watch the light as you wiggle the wiring. You can make a test light out of automotive bulbs. Say a headlight bulb for the higher amperage fuse and a taillight bulb for the lower amp fuse.

 

[Oz_Kioti]

This might be totally irrelevant, however, for what it's worth:

A mate's Vermeer SkidSteer working on our place, suddenly wouldn't start. After much probing and part-dismantling to get at the fuse next to the starter motor, we had a closer look at the accessible 4-fuse block next to the battery, removing the fuses one by one. We found the problem:

Rather than replacing the fuse block, we fitted an external fuse holder and problem solved:

Connectors carrying decent current are potential sources of grief. I have a Braumeister 50 beer-making machine, which has two heating elements - a 1.3Kw and a 2.0Kw - connected to the main control box with fancy German-made locked-in-place connectors. BUT, good as they are, one of those went dodgy, with the tell-tale signs of arcing and getting very hot. Replacement connectors and sockets on their way.

 

[TheParkRanger]

Thanks for your quick replies, OZ and KW.

I forgot to ask a pointed question:

Where is/what is the "stop lamp" so I can start from that load and work back to the fuse block. I'm confused by both the manual and the diagram, if that's the parking brake lamp or the brake lights (wait, does this tractor have brake lights) or something related to the light on the instrument panel?

 

[anomad]

Stop lamp is usually what we call a brake light here in the States. I'd take a good look at those up on the canopy first. I've had a lot of japanese cars and equipment.

And not troubleshooting specifically, but can you spend 45 minutes with a pressure washer on it? That would make working on the dirty girl a little easier and maybe totally not happening on your job site... LOL

Edit: I had an old Isuzu in high school that would blow fuses if you had something like a bad license plate light bulb. Maybe check all the light bulbs and eliminate that variable.

 

[Oz_Kioti]

I just printed out the circuit on an A3 size sheet (for clarity) to see what the link was with the clutch pedal blowing that fuse when pressed.

I'm not a sparkie, but comparing what needs to happen in my Kioti, I'm assuming:

The 'Key Switch' sends power via a 5amp fuse to: the PTO switch, the clutch pedal switch, the seat switch, and the seat turn switch.​

​

Each of these switches sends power to the ECU if conditions are met - ie the PTO is OFF, the clutch pedal is pressed, there's weight on the seat, etc. Then the ECU says OK - fine to engage the starter.​

So my first thought is to check for a short in the clutch pedal switch, which would prevent the ECU getting the GO signal, AND blow a fuse as well.

I'll next look at the brake light fuse issue. That's a strange one! However I have also had weird things happen with dodgy light bulb connections, so yeah, check all those!

 

[KWentling]

There also may be other pages in the electrical with more detail on specific systems, such as lights.

 

[TheParkRanger]

LOL anomad, yeah she's pretty soiled, I gave it a quick garden hose down in the morning twilight, power wash definitely needed.

Okay well here's a update:

- We're back in the barn (yeah)
- I disconnected the brake lights — 5amp fuse still blew on key turn to start (one click later)
- so I thought... what if I just tryyyy to start without the 5amp fuse in at all and... IT STARTED

Which means?
- an open circuit is better than a broken circuit?

Isn't a broken fuse the same as having no fuse? How does that make sense?

I'm super scratching my head at this one.

Also not completely scientific in that I temporarily have a 40amp slow blow in the 30amp spot since I was down to my last 30amp. I think I've gone through 50-60 fuses total of both types in trying to hunt down this gremlin. Time to reorder some of those so I can tech this in the barn where all my tools are.

I'm still not sure how the 30amp and 5amp are related (anyone able to follow that trail on the wiring diagram?)

I appreciate all the responses, guys. Thank you KW, OZ, and anomad for talking this out. I've been here before, so I know it's not yet licked. I'll keep updating since I hate dead threads where the outcome is unknown.

 

[Hay Dude]

Does this model Kubota have a PCM (a computer box)?
I had 2 different Kubotas that had PCMs that went bad.
Symptoms included constantly blown fuses and complete loss of certain electrical functions. PCM replacement was quoted at about $5,000 for one of my Kubotas.

 

[KWentling]

LOL anomad, yeah she's pretty soiled, I gave it a quick garden hose down in the morning twilight, power wash definitely needed.

Okay well here's a update:

- We're back in the barn (yeah)
- I disconnected the brake lights — 5amp fuse still blew on key turn to start (one click later)
- so I thought... what if I just tryyyy to start without the 5amp fuse in at all and... IT STARTED

Which means?
- an open circuit is better than a broken circuit?

Isn't a broken fuse the same as having no fuse? How does that make sense?

I'm super scratching my head at this one.

Also not completely scientific in that I temporarily have a 40amp slow blow in the 30amp spot since I was down to my last 30amp. I think I've gone through 50-60 fuses total of both types in trying to hunt down this gremlin. Time to reorder some of those so I can tech this in the barn where all my tools are.

I'm still not sure how the 30amp and 5amp are related (anyone able to follow that trail on the wiring diagram?)

I appreciate all the responses, guys. Thank you KW, OZ, and anomad for talking this out. I've been here before, so I know it's not yet licked. I'll keep updating since I hate dead threads where the outcome is unknown.

I urge you to set up a test light to replace the fuse. It's the way the pros find shorts. Easy to do. No more feeding it fuses. The light is current limiting so no danger to the wiring. Easiest is to find an old headlight or taillight assembly and rob the bulb socket and some harness. Connect a length of wire to it with appropriate spades to plug into the fuse holder. Use enough wire so you can get the bulb up where you can see it. If you have an amp clamp you can monitor the amperage too to know what load (normal verses dead short) you are seeing. Changing light brightness when wiggling wiring (or pushing the clutch pedal, etc.) is what you are looking for.

 

[mllud]

Take a good look at those fuse holders. I have a NHlx865 that had random electrical glitches that I chased for years. On day my knuckle brushed across the 6 gang fuse holder and I heard a solenoid rattle. I wiggled the fuses, and 3 fuses were loose in the socket. I bent the clips to tighten them back up but upon inspection the fuse holder was a piece of junk. Crimped connections on non-stripped wires with small spikes into the wire. The clips aren't spring steel.
Those gang type fuse holders can be replaced with better fuse holders with screw connections and a plastic cover for not much money.
I installed a 10-gang fuse holder and has a few spare openings for future options. No more gremlins!
I didn't suspect my fuse holder for problems and should have. They are not well made like a lot of the connections on modern wiring harnesses. Why they skimp on wiring harnesses is beyond common sense.

His won't find your short circuit but just a place to look at your connections.

 

[Roadworthy]

Look the wiring itself over carefully. Mice may chew or eat the insulation off the wires allowing them to short to ground in hard to get to locations.

 

[walnutman]

You can pick up some resettable auto fuses on Amazon. But the test light method is the way to go.

 

[Redlined0002]

Kubota M59 was made 2008-2015. It doesn't have a ECM. Your problems are probably under the instrument cluster in the dash. That is where the fuses both have a common denominator. Probably have wires chewed thru by a mice or squirrels

 

[YanmarFever]

Florida is the capital of wire chewing mice. They chewed the wires on my dodge ram quite a few years ago, 3 times I had to repair them.
I bought a bottle of spearmint oil and I poured some on a rag tied underneath the truck. It seemed to work because they haven't been back in a few years.
They love to eat the coating on the wires, they are made from a soy based material.

 

[Aquabird]

I think like 2 of the latter posters, where mice chewing could be causing 1 or 2 wires to touch a grounded surface. Wires rubbing together or rubbing on something could wear off insulation and allow them to either short together or ground out.

 

[rScotty]

I have an M59 and would be glad to help. The M59 is a classic - one of the best things IMHO that Kubota ever built.

But how in the world are you going to find anything as dodgy as an electrical problem when the tractor is that dirty? Get 'er cleaned up and you stand a chance. Seriously cleaned up.
If you are blowing fuses then that is your best clue. That is telling you where the problem is.

One side of the fuse connects to the battery and the other side goes to whatever circuits that fuse is protecting. Somewhere in whatever is being protected is where the problem is. You know it has to be either a bad component (which will probably show signs of overheating)......, or more likely just an abraded wire periodically shorting to the frame. This is basically eyeball work, not skull sweat. Mechanics hate tracing wires, but that is what you have to do to each wire and to each connection.

Yes, a poor or corroded connection can definitely cause enough resistance to blow a fuse, so suspect connections as well as abraded wire.

Using a 12 volt taillight instead of a fuse is a great idea. It limits the current and won't burn out.

Yes, the M59 does have a primitive computer, but they are pretty bulletproof. Besides, it it ran OK for an hour like you said, the computer - and the stuff under the right side "dashboard" display are not the problem. They are well protected and the only thing hat goes wrong there is when water has been getting into the key switch. But if it sometimes starts and works OK, that side dash is OI

My guess is the problem will be obvious once you clean it up.
The big clue is the #7 fuse 5 amp fuse and everything downstream of it. There aren't many things. on #7, so start there. Think simple.

Yes, mine makes a loud "clack" when the ignition key is turned to the first position CW. I thought that was the glow plug relay, but it might be the fuel relay. More likely as i listen to the clack, I think it is both happening at the same time.

You don't need a high dollar Kubota mechanic, you need a teenaged electronic geek with a VOM, a lightbulb, a brush with soap & power washer, a long-handled inspection mirror.... who can read a schematic and has a relentless attitude. Physical flexibility counts when tracing wires.

rScotty

 

[sunandsand]

Agree - clean it up real good first and get a voltmeter, follow the wires. Think of it as plumbing - somewhere the water is leaking out - the insulation is damaged - and that blows the fuse.

Hardest part is tracing the wires. The schematic is drawn so it makes sense as to the electrical layout but finding the corresponding parts on the tractor is another story. The wires are color coded, white with a red tracer (stripe) for instance so they are easy(er) to follow. Each circuit will have its own color as well. Grounds are usually black or brown, hot is red.

Look for chafed insulation - wires too close to something that moves. Look for burnt/melted spots on the insulation (which is why you need to clean it up before you try to troubleshoot it). Look carefully, I've seen failed light bulb sockets (plastic insulation inside is melted) which blew a fuse whenever the brakes were applied. Examine every piece of the problem circuit, sometimes these electrical gremlins are subtle.

A couple of hours cussing sure beats a $6K wiring harness - and if it is a bulb socket (for instance) you'll still have the problem but be $6K poorer.

Nice thing about electrics is they aren't heavy, greasy, or under high hydraulic pressure. I don't know anyone who has ever been hurt because a fuse fell on their foot . . .

(Years ago I used to teach this stuff in a vocational school. We took the halt, the sick and the lame and tried to make motorcycle mechanics out of them - with varying degrees of success.)

Take a deep breath and relax. This is head work, not grunt/groan/lift/ouch/damn work. Go slow, you'll figure it out!

Best Regards,
Mike/Florida

 

[grsthegreat]

How the he** can a wiring harness cost that much. Mice ate mine somewheres…could not locate problem. I didnt feel like removing all the loom and tape, so i replaced harness. Kioti only charged me $295 for entire harness, and it took about 3 hours to install it.

I kept the old harness always meaning to trace and repair it…..someday.

 

[dnw64]

How the he** can a wiring harness cost that much. Mice ate mine somewheres…could not locate problem. I didnt feel like removing all the loom and tape, so i replaced harness. Kioti only charged me $295 for entire harness, and it took about 3 hours to install it.

Well, first off, the OP opined that the dealer was getting sick of working on his tractor, so likely the price was inflated.

Secondly, $295 sounds woefully inadequate for a wiring harness on a tractor that was built in this century. An 8N, OK.

Similarly, I can promise you that even if a factory trainer Kubota tech could replace it (mind all the grime that is in the pics) in 3 hours, ain't no way that is the published labor cost (no doubt in part because of the anticipated grime).

Nevertheless, $6k is over the top. Most likely due to my original point.