I have a 2018 B3350su wiring issue.

[Paul Horridge]

After running it a couple of hours, it shuts off and won't start. Took it back to the Kubota shop and they changed out a burnt fuse, second one down on the left. This is the second time with the same problem. They told me that I need a new wiring harness, for the price of $2000. Plus labor. Or I can just bring a bag of fuses. They think there is a break in a wire somewhere. Any ideas?

 

[PoTreeBoy]

Welcome aboard. A break in a wire won't normally cause a blown fuse unless it is touching a metal part, causing a short to ground. You can connect a small light bulb where the fuse goes, remove the fuse. Then start wiggling wires until the light glows, that's where the short is.

Harbor Freight has this tool, which might help

 

[1810]

If there is a short, which it sounds like, pull open a connector you think is associated with it &, with a multimeter, check what pins are going to ground &, if you have enough advice & diagrams you might find the circuit with the problem. If you then get an idea of what be the problem, go to the other end (if you can) & do the same in reverse, This isn't a guaranteed solution to Utopia but might help you narrow it down to a single circuit. It's by no means a 'quick fix' & could take hours but hunting shorts can really test your patience to the limit!....but check what stuff you can check that's going to ground or is connected to a circuit it shouldn't be... if you can.... & don't forget to test your relays, in case one has somehow failed....you never know? I just happen to have had a rat amongst the wiring on my Nissan Frontier & somewhere, on the loom, it's been chewing... End result....no wipers, no lights, no fan heat or aircon + other things...but I still have ignition & blast off! I do sympathise with you, however.

 

[North Idaho Wolfman]

One work around for intermittent shorts is a circuit breaker, just like a fuse but you can either reset it each time it blows or you can get the self resetting kind.
Don't recommend this as a permanent solution but it's good for temporary trouble shooting.

 

[GreensvilleJay]

agree, fuses blow ,when 'something' causes a short....so
1st step, get the WorkShop Manul (WSM) and study the electrical wiring diagram.
2nd, find out just what that fuse, 2nd one down on the left' supplies power to !
Can you recall when it happened, say bouncing up-down on the seat ? Maybe engaging a PTO lever ? Turning on the radio ?? That should narrow down where to look.

 

[SDT]

After running it a couple of hours, it shuts off and won't start. Took it back to the Kubota shop and they changed out a burnt fuse, second one down on the left. This is the second time with the same problem. They told me that I need a new wiring harness, for the price of $2000. Plus labor. Or I can just bring a bag of fuses. They think there is a break in a wire somewhere. Any ideas?

Curious? Have you had emissions issues?

Your symptoms, aside from the purported blown fuse(s), are consistent with B3350 emissions issues.