Kioti NX5010 blowing fuse for PTO/4 wheel drive

Waynr1 · Aug 16, 2019

Just purchased a new NX5010 and the unit would intermittently blow the 15 amp fuse for the PTO/4 wheel drive circuit. PTO and 4 wheel drive would obviously not work then.
Solution is the unit had a defective diode near the PTO solenoid, The solenoid is on the right side of tractor just behind the Hydro filter. Wrapped up in black tape on the wiring harness is a small rectangular diode say 1/4 inch wide by 3/4 inch long. Dealer replaced the diode and so far it appears to be working good.

Waynr1 · Aug 22, 2019

Waynr1 said:
Just purchased a new NX5010 and the unit would intermittently blow the 15 amp fuse for the PTO/4 wheel drive circuit. PTO and 4 wheel drive would obviously not work then.
Solution is the unit had a defective diode near the PTO solenoid, The solenoid is on the right side of tractor just behind the Hydro filter. Wrapped up in black tape on the wiring harness is a small rectangular diode say 1/4 inch wide by 3/4 inch long. Dealer replaced the diode and so far it appears to be working good.

Sorry the above did not resolve the situation, still blowing the fuse. Back at the shop.

justman777 · Aug 22, 2019

I dislike intermittent electrical problems. Very hard to diagnose. I suspect it's got more amperage going through it than it should all the time, and the fuse is just slow to blow. Wonder what a multi-meter would indicate for amperage being used...

Was the fuse blowing when the 4WD and PTO were engaged, or did it just blow without either being on?

DieselBound · Aug 23, 2019

I'm kind of thinking I recall someone having a problem with their PTO switch, they got it replaced and all was well. I'd look to see what sort of voltage is being held up when each were engaged on their own. Might be one of them has a bit of a short and when both are activated it overwhelms the fuse.

DieselBound · Aug 23, 2019

For educational purposes (from the Service Manual):

The solenoids for the PTO clutch and 4WD clutch are all equipped with electrical ON-OFF solenoid valves which are
operated by electromagnets and return springs in the same structure. Each solenoid's spool has an orifice structure
to reduce operating shock when opening the spool. On the other hand, the solenoid for PTO operation is equipped
with a time delay valve for smooth operation.

The spool of the time delay valve is normally open by its return spring. Therefore, when the PTO solenoid starts to
open, hydraulic fluid is drained through the time delay valve before it is supplied to the clutch piston. This is why the
clutch is not engaged firmly in the initial operation of the solenoid. However, as time passes, pressure is built in the
pilot line of the time delay valve which is then closed only halfway. Then, a small amount of oil is discharged through
the orifice spool in the middle section and the remainder is supplied to the PTO clutch piston which then makes the
PTO start to rotate. As more time passes, the amount of oil supplied through the pilot line of the time delay spool is
maximized, so the time delay spool is completely closed. Then, all the oil is supplied to the PTO piston to compress
the PTO clutch firmly, and this completes the PTO operation process for approx. 1.5 seconds.

Threepoint · Aug 23, 2019

Waynr1 said:
Sorry the above did not resolve the situation, still blowing the fuse. Back at the shop.

Waynr1, welcome to TBN! Thanks for posting about this. Glad your dealer is on it. I'm hoping it's something simple like a chafed wire, or a problem with the PTO switch. Tracing pesky electrical issues like that must be one of the most irritating things the techs have to deal with.

Looking forward to hearing how it resolves.

ritcheyvs · Aug 24, 2019

Here is a link to similar problem with DK45.

IMO, the "fix" in that thread is not conclusive but owner has not reported additional problems. The entire thread may contain clues for you.

Good luck.

Waynr1 · Aug 24, 2019

A week later the issue continues. I was able to mow for about 2 hours with out the fuse blowing. I would shut the tractor completely off, then on again, start the PTO and it would turn on and off correctly, I did this intermittently during the two hours. Also went over very bumpy ground and that did not affect it. Then after about 2 hours it blew the fuse. So after sleeping on it, I decided to install a new fuse and simply use the box scraper. So now I was using 4 x 4 a fair amount, but not 100%, after about 2 hours of working properly the same 15 amp fuse blew.
Back at the shop.
Please note that my dealer is really trying hard, they are making this tractor their #1 issue. When I call they come a running. Secondly they are bringing out their Demo unit DK4710SE each and every time.
I hope to post a solution.
I also did another post about ground speed surging.
Comments were made that if not resolved soon they will get me another new one.

Waynr1 · Sep 10, 2019

I believe that I can finally post an update/solution to the original issue of the PTO/4 wheel drive fuse blowing.
When the unit was assembled, the wires under the switches (located to the right-rear of the seat), were not wire-tied appropriately to the side. The Red wire going to the white plastic connector ("Molex Connector") to the PTO/4 wheel drive switch got caught on one of the levers. This slightly pulled the red wire out "Molex" connector. Which in turn caused an electrical problem blowing the fuse. Metal connector to red wire re-crimped and fully reseated into the Molex connector. Have over additional 10 hours of operation without issue.