I have a 4 year old John Deere L120 where PTO switch will not engage the mower. Sometime, with the reverse override switch pressed, the mower gets engaged when going in reverse.

When I get off the seat, the mower starts engaging and the engine gets switched off.

Any help is greatly appreciated.

Billy, August 2008

It takes a bit of doing, but, cut out all the excess switches. Rewire the whole thing. After numerous hours & money wasted, I decided to rewire the whole mower. No more problems!!!!!
By the way, don't bother with JD. They sell parts at inflated prices, whether it fixes the mower or not. Get a case of beer, buddy & a whole bunch of wire & connectors!!!!! DIY!!!!! RIGHT!!!!!!!!!!!!!!!!!!

Barry, April 2017

The pto wires kept breaking on my L130. Repaired them 3 times. After the 4th time I did some investigating and found the clutch retaining bracket had worn and let the clutch vibrate excessively. I removed the bracket, cleaned the worn area down to bare metal, and soldered a penny on each side. After grinding the edges a bit, it fit the hole perfectly. Seems to have solved my problems.

Marvin, March 2016

Problem solved. I had the same problem as most of you; my pto tore loose two and destroyed the cables beneath. I had to replace the white cabling up to the pto, but the twin black cable connector seemed okay. The pto stopped again this morning, but would engage momentarily when I started the mower from off the seat. Voltage would register at the connector with a multimeter when I was off the seat, and the mower running, but nothing when I was seated. The problem was one of the two black cables at the pto on the spade connector. The wire at the female spade was mostly broken, but not completely until i twisted it. I cut the wires off, replaced the click in connector spade with a new one, rewired and soldered it for good measure, and everything worked beautifully. Basically a $1 dollar repair. It was so strange though seeing 30 volts at the connection before the repair. Hope that helps.

Bruce from Ohio, May 2015

I have the same issue with my PTO and went to the dealer. They tried to sell me the full harness ($216 + install). I may have fallen off the turnip truck a few times but for $300 bucks I'll redneck engineer it and put that money in the jar marked Kubota fund...

Todd E, July 2014

I think most mowers are having the same problem. It seems to be a issue with the ground circuit at the clutch (PTO) If there is a bad connection at the plug or broken wire the safety circuit acts strange. seat switch will appear to be working incorrectly. Opposite of the norm. JD had made a repair to the plug a few years ago and the crimp that they made was bad. (poor connection) I repaired the connection and the mower is fine now. The root problem is a high resistance at the connection and the high current that the clutch draws cause a floating ground. Not battery zero.

PJ,

I would like to know more about the issue you had with your mower. I currently have one in my shop that is acting crazy. The engine will start and run great, if you pull the PTO nothing happens but with the PTO switch pulled if you lift up off the seat the clutch kicks in but the engine dies. I tested the two wires going to the clutch one should be a hot (when the PTO is engaged and brake released) and the other should be ground, correct? Well I have about 14 volts while running on the hot wire and nearly 40 volts reading on the ground, that's crazy I know considering the alternator is putting out correctly and the voltage regulator is putting out only 14 volts so I don't know. Could you tell me more about your repair and issue

Thanks James

James, June 2014

The L series tractors have a design defect. As the mower gets older, the PTO clutch torques sideways and the repeated flexing breaks off the 2 wires. The way to fix this is to place a piece of fuel line on the pin which is in a slot of the PTO. This prev ents the torquing. This drove me nuts until one dealer finally fessed up with the fix..after I bought harnesses and wasted my money. I will never, ever buy a JD again. The machine is junk

dennis, May 2014

I think most mowers are having the same problem. It seems to be a issue with the ground circuit at the clutch (PTO) If there is a bad connection at the plug or broken wire the safety circuit acts strange. seat switch will appear to be working incorrectly. Opposite of the norm. JD had made a repair to the plug a few years ago and the crimp that they made was bad. (poor connection) I repaired the connection and the mower is fine now. The root problem is a high resistance at the connection and the high current that the clutch draws cause a floating ground. Not battery zero.

PJ., May 2014

Same song and dance here. Blades stopped, and found 2 black wires loose at the bottom by the clutch. Problem not sure where they were connected. Anyone have a diagram or picture of where these go. That they could email me I would appreciate it.

Dons, April 2014

Mine has just 91hrs...engine runs perfect, but engage pot and it dies as if I turned off the key...will have to check wires now that I read that could be the culprit. Addl advice greatly appreciated.

Kurt, October 2013

Problem: Clutch broke free from mount.
Fix: Bend a piece of flat steel and bolt it in place from clutch to mower deck mounting area on front crosmember area.

Problem: Clutch switch inop.
Fix: Hardwire positive and negative connections from clutch to battery and install a simple on/off switch and secure in dash...I used a semi dash board switch...no problems with the safety harness since doing that.

Fyi: I think the clutch in this tractor overheats and melts the wiring connection to it. So I'm going to try and modify the assy on a brand new more expensive clutch...I'll post my results when I test. Hope info helps all.

Pauly, July 2013

Came home from vacation, grass was high, so jumped on my L120 to cut grass and battery wouldn't turn starter over. Jumped it from car and it started right up. Drove over to grass and blades would not engage. Remembered this spring that battery was down even though I had a trickle charger on it all winter. Decided to fix battery first and was surprised to find that the new battery also fixed the blades not engaging. I guess once it was started the battery just didn't have enough juice to hold pto clutch engaged.

John in Kentucky, June 2013

Have had the same problem several times. Bought 1 harness from local JD dealer for $21.00 two years ago. Same harness is now $58.00. Talk about inflation. Have seen it 1 other place cheaper. Local JD sold me a body for the pto connector for 0.38 cents. Good of them. I had two of the type Packard 56 female disconnects left from another fix and noticed that the previous harness had a couple of the same type connectors already crimped so I used the dually crimped for the black wires and re-crimped the yellow wire all from stripped wire left over from the harness I got from local JD. Used some extra split plastic conduit this time. I should sell it while its running and get a better mower. Never JD again because of this.

dsgnr1, April 2013

Just bought a used L 120 from a JD dealer only has 35 hours on it, mowed my lawn for 10 minutes and blades stopped turning. Metered the PTO switch, shows that about 3 volts is getting to the clutch. I this enough to switch it on? I will try a 12 V source from battery charger today to see if it engages. Could also be bad contacts inside black spade plug. Thanks for all the posts. Maybe something will work.

Tipster, November 2012

I too have had nothing but problems with my L120. Only the latest is the PTO Clutch. My clutch broke free of the mounts and spins with the shaft. That of course broke all of the wires to the clutch. Is it going to be worth it to fix (replace clutch and wiring harness) or will I be fighting it over and over again?

Sean, April 2012

FWIW, after replacing the spade plugs and wires numerous times, I went with much heavier wiring and lots of heat shrink tubing as far back as possible to solve the issue of burnt wires at the pto clutch connector. I also wired-tied the wires to the front crossmember directly in front of the connection so the wires were not being pulled off to the side so hard like it originally was. This has solved the wiring problem.
But alas, now I have power to the pto clutch, but not engaging. I guess I might need to replace the clutch....

jk, August 2011

I too have a JD L120. After replacing spades, a wiring harness and the clutch assembly, the tractor does exactly what it did before...NOTHING. All switches test out fine... RIO, Seat, etc... no success in getting the blades to spin... unreal. Any other solutions?

TK, August 2011

I have the JD L120.....nothing but problems, I will NEVER purchase any John Deere products ever again, overpriced parts and poor engineering.

I had a Craftsman before for 12 year in FL...I never changed oil, replace spark plugs once and never gave me a problem, it rust out because I did not care for it but the engine was still running!

Ed Montana, July 2011

I had the same problem and this site saved me big time. Luckily the reverse and seat wire fell off so I can get off the mower and back up without the blade stopping. I fixed the PTO wires and all seemed fine until the black lead broke off again. I now soldered both wires and hope it lasts a little longer. Does anyone have a permanent solution? I found a PTO wiring harness for $21 but I'm not sure it's the right one.

Youngster, July 2011

I have the same problem. For the last few years I have operated my JD L120 with the seat switch and the reverse switch disconnected. All has worked just fine. But all of a sudden when I lift up on the electric pto switch the engine dies. The headlight thing intrigues me and I guess I'll go out and look for that.
Does anyone have an electrical diagram they could share with me?

Greg Freeman, June 2011

I have a John Deere L120 with about 260 hours on it. I have had to repair the connector/wiring harness to the PTO SEVERAL times. The wires break at the base of the connector from the vibration of the PTO clutch. You would think that John Deere would have a fix for this other than replacing the harness (a real pain). It needs a more flexible wire.

Harlan, June 2011

I've had the same problems as all of you. I went to the JD dealer on Saturday to get some new spades for the plug attaching to the pto clutch. This guy (after having spoke to 2 or 3 others at the same place) literally said "what do have an L120?" I surprisingly said "why yes I do". He proceeded to tell me they had that problem before and couldn't figure it out until they finally looked underneath with the deck running and found the ptop clutch vibrating and shaking the wires enough that they break off. They replaced the pto clutch and everything was fine. $160 later, but he was right! I hope this helps relieve some of your frustrations!

KB, August 2010

I also had the same issue. The wires to the clutch broke. I replaced them for $.19 by a new wire connector that worked. Now it stopped again. When I checked the clutch I found a long brass wire stuck inside. Does anybody know what type of connection goes to the clutch itself. I am wondering if the connector that you hook the wire harness to is damaged in the clutch itself.

Not running like a deere, July 2010

Thanks for all the suggestions!! Blades stopped while cutting. The switched seemed to work fine...ie if you pto switch up and tried to go backwards it would cut off or if you tried to get off seat while pto engaged mower would cut off. Tried, looking for loose wire - found none, got out air compressor and clean around switches, follow wires from pto switch down to underneath...still no solution, cursed JD, when back on line found this site, jiggled more wires including the light and clutch underneath mower, found this site, looked again for loose wires, cursed JD some more (why didn't i buy a cub cadet), gave up and called dealer...got voice mail (woo hoo!!), jiggled some more wires...and the blades worked...cut for about 1/2 hour. Not sure how long it will last but jiggling, cleaning looking for lose wires...saved me a service call and who knows how many hundreds! Try, try and try again.

steve, July 2010

I had the same problem with the vibration from the clutch causing the wires from the PTO to loosen and break. Put new connector on the wires, reattached to the clutch and everything is working for now.

Dan, June 2010

Had same problem with PTO wires breaking at the clutch. Clutch also has a lot of vibration, which I believe causes the wires to break. After repairing the wires at the clutch, it then would not engage at all. Without a wiring schematic, I could not tell where I was loosing power. I ran 12 volts directly to the clutch and the PTO engaged. Lost voltage somewhere .

Tony, June 2010

After reading other postings, I found my yellow wire to the PTO clutch to be pulled out of the spade plug. I got a new spade plug at Advance Auto, the kind you can heat and it melts around the wire to keep the weather out. This fixed the problem. This weekend I was mowing and it cut out again. The black wires and yellow wire all still seem to be connected to the pto. Here we go again. I will have to try to find the problem again.

Tom, May 2010

Thanks to this web page I saved a bundle. I was about to start the switch replacement routine when I read about the wiring harness problems. Found loss wires mentioned by Lemon and repaired in 1 hour-free.

buyer2, April 2010

I too am trying to diagnose the same issue on a friends L120 deere. three switches burned up, and the guy had the clutch replaced. I found a hot melting into the neg. for the seat kill switch. I figured I had fixed it, but had to think again when it stopped working after five minutes. there is something in the wiring. I will be sure to check all of the above potential problems first and will post what the problem is after I find it. I would hate to spend $95+ on a new wiring harness if I don't have to. Thank you for your posts

James, April 2010

I had the same problem with the PTO not engaging. Replaced the yellow switch twice at $40 a pop and it would work for a few minutes before stopping again. JD Dealer diagnosed clutch defective and replaced at cost of $700. Said it was due to too much fine dust getting into clutch during drought?? Worked for a year and now it has stopped again. Prett close to trashing the machine and trying a different brand.

Phillip Langworthy, March 2010

I had the same problem today. My mower deck just shut down in the middle of mowing.
After reading this post, I quickly found the loose wire,(the black wire at the clutch mentioned by Mike) and jury rigged it enough to get the lawn mowed.

Thanks Mike!!

Kevin, September 2009

Not an answer but a big thank you to everyone on this blog....I was having the same problem...PTO not engaging....went to two dealers 4 times....about 120 miles of driving for $40 worth of switches-all of which were needless!

The comments from Lemon 120 were spot on!

Looked at the same wiring problem with the ground wires on the connection on top of the clutch for the mower!

Thanks for the help....its working great now!

Steve, August 2009

My 2003 L120 from a big box has been a nightmare for a variety of reasons this being one of many. The wire harness has been replaced/spliced and repaired multiple times over the years and now it also burns in various places all along the chassis for no apparent reason. Is there any way to override the electronic engage? I am tired of replacing harnesses but that appears to be the only solution.

Lemon120, September 2008

I have the same mower and had the same problem with the PTO. The problem was some what intermittent. The electric PTO switch would either do nothing at all or do nothing until the reverse drive peddle was engaged then the engine would die.
Look at the blade clutch in the front of the tractor under the engine. There is a plastic electrical contact in the front of the clutch on top with two black wires and one pale yellow wire. On my mower, one of the black ground wires was broken inside of the insulation near where the spade connector is crimped on. It was not easy to find. Because both wires were connected to one spade, the spade showed good continuity when checked with an ohm meter. To fix mine I had to remove the spade from the plastic housing and solder the broken wire to the good wire.
So far it has fixed the problem. At least I have mowed my lawn today.

The John Deere service technician I talked to said, the problem is junk wiring harnesses purchased overseas. He said to look where I’ve told you to look but if it didn’t fix the problem to replace the whole wiring harness.

Good luck.

Mike B, August 2008

After searching the net for a week, discussing with my John Deere parts & services group, buying 3 new saftey swithches... and the JD folks telling me that if the switchs didn't work I probably had a major wiring problem and would have to completely redo the wiring harness... I then found a reference on another site, regarding another model mower, to a potential ground wire issue at the PTO itself.. While I checked the ground and all appeared to be fine, I found loose and reconnected a leed that went to the front right headlight... I tried the mower and PTO and all worked fine, I assumed that in the process of checking the pto ground maybe it was loose and I resecured it, and that was the problem... but thinking the headlight leed didn't have a chance in heck of being the problem, I disconnected the ground again from the right headlight and the PTO would not engage again, and all the symptons of this post reappeared... I reconnected and all worked fine again... This blows my mind that a ground at the headlight, a gound that also appeared to pass on through to the left headlight and was connected there, would cause these symptons... This problem is definetly caused by a ground issue and I guess could be located anywhere from the battery to the headlights... Weird!!! And that the JD reps would not tell me this?????

Ron, August 2008

Billy, I'm having this same issue and I've been searching for an answer off and on for a week now... I've seen several post of this same issue, but no answers.. I've replaced the PTO, Seat & Reverse Override switches with no luck... I've seen one reference to the ground wire coming from the pto as a possibility, but haven't tried checking that yet.. If you or anyone has an answer, the help would be appreciated. Thanks, Ron

Ron, August 2008