2017 kubota bx25d - tachometer inoperable

Illinifan · Aug 22, 2023

Hi, I just purchased a bx25d and noticed the tach doesn't work. When I start the tractor the digital tachometer needle sweeps to high rpm then rests at 0 rpm and stays there. I have checked the fuses and they are good. From reading other posts apparently the tachometer operates from pulse from alternator signal. As many bx models in use I would think/hope others have experienced this too. I plan to test battery and alternator output tomorrow. Any help or advice is appreciated. Thanks

frogpond · Aug 23, 2023

On my bx25d, I had this exact symptom a couple months ago. It turned out that my fan belt was loose. Try tightening it. It's a little hard to get at the lower bolt on the alternator without taking off the engine housing, but it can be done. In my case, the belt was too stretched out to adjust any further, so I had to replace it. I hope you don't have to do that, as it's a pita. But the gauge problem was instantly solved. Also, of course, it should help the alternator and the fan to operate better.

Illinifan · Aug 23, 2023

Thanks Frogpond, I noticed the belt was loose yesterday but didn't think it was loose enough to cause that so you give me hope it will. I will post results after I get a chance to check it. I would much rather replace the belt than the alternator ($) if I have a choice.

Illinifan · Aug 24, 2023

Frogpond, I tighten the alt belt but unfortunately did not fix the tach. For some reason there is alot of oil residue on the alternator. This tractor is new to me so I'm unsure why. I confirmed the alternator is not charging the battery 12.34V with key off and actually 12.28V running. I would appreciate any diagnostic suggestions. Thanks

Illinifan · Oct 5, 2023

Fixed.Just wanted to provide update with resolution. There were 2 problems. I replaced the alternator with a genuine kubota alternator ($410 ouch) which fixed the charging problem but not the tachometer / hour meter. I crawled underneath tractor and found a broken red/yellow wire broken close to the connector to the fuel pump. I repaired wire and it fixed the the tach and hour meter. Hope it helps. Thanks.

j13smiley · Oct 5, 2023

That wire stopped the hour meter also? I assume you bought this used?

Illinifan · Oct 5, 2023

Yes, the hour meter and tach use the same wire.

s2kskibum · Nov 6, 2023

Curious - were you popping any fuses? I am dealing with a 10a fuse issue which kills all the idiot lights and the tach is behaving exactly as yours is. Thanks!

Illinifan · Nov 6, 2023

No, not popping fuses because it was an "open" with wire broken. Not sure If it blew a fuse when damage was done then fuse replaced later because I purchased it that way. You only blow a fuse when there is a short to ground in circuit before the current gets used by the load. You must have a short to ground on that fuse circuit. Good luck

s2kskibum · Nov 6, 2023

Thanks. Had it at a dealership, mechanic could not find anything wrong. I have no confidence in the mechanic. I'll look where yours was shorted, maybe that will be it!

Illinifan · Nov 6, 2023

Does it intermittently blow the fuse or immediately blow the fuse when it is replaced? I've attached the wiring schematic. Which fuse is blowing? Seems like the tail light wiring is a common problem because they tend to hang down are easily damaged.

s2kskibum · Nov 7, 2023

Immediately blows. And the back lights mounted inside the fenders where melted - like the bulbs had overheated. I have taken them out. The mechanic at the dealership said he tried a 30 amp fuse that immediately blew, which was stupid and could have permanently damaged the gauges. I'm picking it up later this week, and will trace the wiring. Thank you for the schematic, that will help!

Illinifan · Nov 7, 2023

I agree, a technician should have known better. No problem. Let us know what you find.

s2kskibum · Nov 10, 2023

Picked it up. They found some things jammed under the seat that damaged one of the safety switches. Never saw these parts before, guess the previous owner had left them there. No tach still, but the fuse isn't blowing. Going to go look at the wiring a bit more and test the alternator.

Illinifan · Nov 10, 2023

At least you can use it. Let me know if you find the source of the inoperable tach. Good luck

s2kskibum · Nov 10, 2023

Fixed! The shop charged me for two hours and a replacement safety switch, could not find the short issue. I got under the tractor back at the barn and found the problem immediately - not in the same place as you, but the two yellow and red and one black wire, completely shredded. I spliced new wires in, fired up and everything is working fine again. Battery being charged, tach and all gauges/lights.

Thanks for leading me in the right direction! Can't believe the "mechanic" could not find the issue - it was so obvious.

I'll sleep better, and am $400 "richer!"

Illinifan · Nov 11, 2023

Great job! There in not much protection for those wires the way they are routed. Glad it worked out. I'm suprised there wasn't more cases with resolution posted given how many complaints there seems to be online.

s2kskibum · Nov 11, 2023

They tried to sell me a new alternator. I said "Sure, order it, but I'll probably call and cancel it..."

s2kskibum · Nov 15, 2023

Small but mighty! This tank was never tied in nor properly installed. It floated this summer a bit. Dug around it a bit, lifted and pulled. Love this "toy" tractor. 1250 gallon tank, with some dirt/water in it.