John Deere LA140 motor runs but mower won't engage

I have a John Deere LA140 that is about four years old. I have recently had issues with the mower engaging then disengaging. After reading other forums, I determined it could be the battery (which was old) so I replaced that and the voltage regulator. After testing everything, that is not a problem. I'm getting proper voltage and the stator is putting out more than ample charge to keep everything going. I also had the common issue with the wire breaking off the connector at the PTO clutch under the mower. At first I just crimped it back on but after the mower quit engaging at all I just purchased an all new wiring harness and installed it. Still no dice. When I try to engage the electric PTO it makes no noise at all, no attempt to start the blades. Does anyone else have a clue as to what this could be? In parts I've spent about $180 at this point. The service call to the local JD dealer will be $139 plus parts so I'm motivated to do this myself but can't keep guessing and spending. Thoughts? Thanks for your help!

hi there.. sorry to hear that you had a run of bad luck.. with your clutch.. did the wire break off at the top of the clutch? if so there is no way of fixing it.. I did a service call today.. concerning a cub cadet clutch.. the customer took it off and put it on.. and yanked the two wires apart.. I would just get a new one.. you can get one on ebay..

Hi,
In my post, I mentioned that the wire had broken off and that I originally crimped it back on but that I just purchased a new wiring harness and installed that. The wiring harness included the plug that goes on top of the PTO clutch. So, that should have fixed it but it's not working. It wasn't hard to install the new harness so I'm pretty certain there's some other issue like a swtich or relay or something like that. I suppose it could even be the PTO switch itself. I did a continuity test on the PTO switch and got a tone when I touched opposite poles so I think that's okay. Still a mystery..
Thanks for taking time to reply.

FHH said:

Hi,
In my post, I mentioned that the wire had broken off and that I originally crimped it back on but that I just purchased a new wiring harness and installed that. The wiring harness included the plug that goes on top of the PTO clutch. So, that should have fixed it but it's not working. It wasn't hard to install the new harness so I'm pretty certain there's some other issue like a swtich or relay or something like that. I suppose it could even be the PTO switch itself. I did a continuity test on the PTO switch and got a tone when I touched opposite poles so I think that's okay. Still a mystery..
Thanks for taking time to reply.

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Time to get out the old VOLT meter. Unplug the connector and see if you have voltage at the plug at the PTO With every thing in the correct position as if you were using it. If not post back and we can go from there. Don't just keep buying parts untill they have been proven bad. Does the LA140 have fuses? If so check them first.


Ken

Thanks, Ken. So, just so I do this correctly, you're thinking I should have someone crank the mower and sit on the seat (so that the safety sensor doesn't shut down the motor) and engage the electric PTO switch while I have the connector disconnected, checking the terminals inside the connector for voltage? I just don't want to do something stupid so is that what I should be doing? Thanks!

FHH said:

Thanks, Ken. So, just so I do this correctly, you're thinking I should have someone crank the mower and sit on the seat (so that the safety sensor doesn't shut down the motor) and engage the electric PTO switch while I have the connector disconnected, checking the terminals inside the connector for voltage? I just don't want to do something stupid so is that what I should be doing? Thanks!

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FHH Yes I often work by myself so I jump the safety out while testing. How many wires are on that plug? I don't have that mower or a print for it. You will need to find what wire has the 12v to feed the clutch and also make sure it has a good clean and tight ground. If you can post a photo it may help. My 2012 Z445 has a 7.5 amp fuse for the PTO clutch See if you have one and check to prove it is good. If you do not have power and fuse is good next would be to check the switch. See if you have power going to the Sw. then turn it on and see if you have power out.

Ken

bollingball said:

Time to get out the old VOLT meter. Unplug the connector and see if you have voltage at the plug at the PTO With every thing in the correct position as if you were using it. If not post back and we can go from there. Don't just keep buying parts untill they have been proven bad. Does the LA140 have fuses? If so check them first.


Ken

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Also be very carfull with motor running you may wiggle a wire and the blades could start moving. To be safe you could remove the blades. To prove the clutch good you can take a wire and hook one end to the pos. side of battery and touch the other end of the wire to the clutch feed wire ( this will bypass every thing ) and see if it clicks do this with motor off so you can hear it if it does not it could still need a ground. Sometimes they use a ground wire or use the metal part of the clutch body as the ground.

Ken

bollingball said:

FHH Yes I often work by myself so I jump the safety out while testing. How many wires are on that plug? I don't have that mower or a print for it. You will need to find what wire has the 12v to feed the clutch and also make sure it has a good clean and tight ground. If you can post a photo it may help. My 2012 Z445 has a 7.5 amp fuse for the PTO clutch See if you have one and check to prove it is good. If you do not have power and fuse is good next would be to check the switch. See if you have power going to the Sw. then turn it on and see if you have power out.

Ken

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Hi Ken,
There are three wires...two black ones and a yellow wire. There is a picture in this forum that I have seen with this same problem. I will try to find it and post it. I only saw one fuse (like an automobile fuse) that was a 20 amp fuse near the ignition and battery. Is the fuse in your machine an inline fuse that is not visible outside the wire? If so, I may need to look more thoroughly. I can also find the wiring diagram which should also help in that regard. I'm a little out of my element (I'm an accountant) but trying to be a mower repair guy. I should be able to try this test this evening when I get home then report back. Thanks again!

Best regards,
Frank (FHH)

FHH said:

Hi Ken,
There are three wires...two black ones and a yellow wire. There is a picture in this forum that I have seen with this same problem. I will try to find it and post it. I only saw one fuse (like an automobile fuse) that was a 20 amp fuse near the ignition and battery. Is the fuse in your machine an inline fuse that is not visible outside the wire? If so, I may need to look more thoroughly. I can also find the wiring diagram which should also help in that regard. I'm a little out of my element (I'm an accountant) but trying to be a mower repair guy. I should be able to try this test this evening when I get home then report back. Thanks again!

Best regards,
Frank (FHH)

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Looks like you have one main fuse My mower has a fuse block like on a car with 5 or 6 fuses most of the newer ones are like that now. If you can post the print we can figure this out. I have scouts tonight with my son so it will be later for a reply.

Ken

Hi Ken,

Attached is the picture of the plug. I borrowed it from another forum but this is how my PTO plug looked the first time it broke. Eventually I replaced the entire wiring harness (this past weekend). I had my son's baseball game last night so I didn't get to test the clutch as you suggested. I will do that tonight. During lunch today I will find the schematic and post it.

Thanks again for your help!

Frank