L3902 PTO won't engage

KYDave

New member

Equipment
2018 M7060 cab, 2024 L 3902 HST, Z231 for the lawn
Aug 12, 2026
4
3
3
GA & KY
Hello,

New to this forum and having a very frustrating time with my 2024 L3902.

Since I've had it (about 3 mos), engaging the PTO has been problematic. It'll work as expected for a while (sometimes a few days of pretty heavy use bushogging with Land Pride 5ft), then I'll be out using it and the PTO just won't engage. There have been times I've Shut off the tractor, started it back up and, viola, the PTO works. Sometimes I can't get it to work, I'll park the tractor for a while and next time I go to use it, it works fine.

When it first happened a few times, I was troubleshooting and flipped up the seat to look at the safety switch and the spade connecters for the wires were not on all the way. I pushed them on more tightly and thought I had it fixed. Used the tractor for quite a bit of bush-hogging for a few weeks and it's worked great. Yesterday, I was clearing downed trees & brush with the grapple and bush-hogging, everything was working great for a couple hours when suddenly the PTO shut off while I was using it. Wouldn't restart, shut the tractor off, waited a few seconds, started it back up and was working again. Did my bush-hogging, shut off the PTO, did some clearing with the grapple, went to fire the bush hog back up and it just will not engage. I haven't gotten it to engage since.

I've jumpered the wires on the seat switch and no-go. When it gets to this state it will not even "try" to engage (no hissing sound from the actuator like it normally does), turning the engagement knob just does nothing. I've done a few internet searches to find a video or something to troubleshoot and all I can find is Lxx01 series videos that have a different seat switch/engagement knob setup than mine. My seat switch is up in the bottom of my seat, not a lever activated switch like the 01 L series and I have a yellow electronic engagement knob, not a lever. Here's a pic of the switch in the seat and the engagement knob in the background:
Kubota3902SeatPTOswitch.jpg


I'm going to do a little more research, heck I can't even find the proper fuse box yet. I'm thinking maybe a relay, but where are they? Any advice, suggestions, or solutions would be much appreciated!

Dave
 

North Idaho Wolfman

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Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Well If only there was a manual that told you such things.... Oh wait there is... Tada WSM answers all.

Look top right of your screen at the envelope. ;)
 
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KYDave

New member

Equipment
2018 M7060 cab, 2024 L 3902 HST, Z231 for the lawn
Aug 12, 2026
4
3
3
GA & KY
Well If only there was a manual that told you such things.... Oh wait there is... Tada WSM answers all.

Look top right of your screen at the envelope. ;)
Awesome Wolfman, thanks for the manual! It's going to take me a while to digest all of that. I have found how to ohm out the engagement switch (knob) to check correct operation. Continued reading and studying I may just figure this out. I'm much better with the mechanical than I am with the electrical though. :( This may take a while.
 

KYDave

New member

Equipment
2018 M7060 cab, 2024 L 3902 HST, Z231 for the lawn
Aug 12, 2026
4
3
3
GA & KY
Hey all, I'm reviving this thread to give an update on my, still not fixed, 2024 L3902. This way I don't have to re-hash everything I've already explained. After getting the info from Wolfman I played around with it a bit more without success. So, I took the tractor to the dealer.

They traced it to the solenoid actuator in the transmission and found a place on a little white wire where the insulation was worn off. Must be causing a short, right? Nope, replaced the actuator and still no PTO activation. Not getting 12v from the computer to the actuator now. Checked all switches, checked all wires and nothing. Replaced the computer (controller). PTO fired up for a bit, then just quit. Checked new computer and all inputs were great, but no output to the actuator. Obviously a bad new computer, right? Replaced the new computer with another new computer and the PTO fired up. Ran it through a few start/stop cycles then left it run for a while with the PTO activated. After about 15 mins PTO just shut off. Now the tractor will stop/start with the PTO switch engaged. Shouldn't do that. but still the PTO won't start back up. Now they have ordered a whole new wiring harness, thinking there's a short in the harness somewhere.

Replaced: Seat switch, PTO switch, PTO actuator, Computer (twice), and now the wiring harness.

They've had the tractor for over 3 weeks now. Thank God they're covering this under warranty!
 
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