John Deere LA140 motor runs but mower won't engage

Morning Frank hope the game turned out good. I sent you a private message I think it worked was my first time on this site check it out and let me know if it worked. That plug is coming from the main harness correct? On your clutch does it have a wire pigtail? Or is the connector hard mounted on the clutch?

Ken

black wires are ground, the other is 12 volt to clutch. with start switch on, pto switch on, jumper wire on seat. check 12 volt to neg. battery, machine frame and to the plug. should have 12 volts all 3 places on your meter. if you do check your clutch then, might have a bad ground. make sure your positive wire is going to your starter and the neg. goes to ground.

bollingball said:

Morning Frank hope the game turned out good. I sent you a private message I think it worked was my first time on this site check it out and let me know if it worked. That plug is coming from the main harness correct? On your clutch does it have a wire pigtail? Or is the connector hard mounted on the clutch?

Ken

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Hi Ken,
Well, we lost but that's okay. Just fun to play the game. I got the message and I understand your point. Thank you very much for the offer. Here's what I did tonight. There is some sort of logic to it in my brain but perhaps not to anyone else. First I checked the new battery once again and it shows 12.54 volts. I disconnected the pigtail from the PTO clutch and, not starting the engine, checked the voltage. Zero of course as it should have been. I turned the key to the On position without cranking and again tested the voltage. Still zero as it should be. Then I pulled the PTO switch and instantly the meter went to 11.99 volts. All of this without being cranked. I think that tells me that juice is getting to the clutch. This is the part that I may need to have cranked the engine (but it wasn't a good idea with neighbors at midnight when I was doing this. I took the old wiring harness and cut off the pigtail from it then stripped the positive wire end and plugged the old pigtail onto the clutch. I then took my jumper cables and connected the red cable to the positive terminal on the battery and the other end to the stripped wire. Nothing moved. I turned the ignition on and pulled the PTO switch and nothing changed. I realize I may actually need to have that cranked to work as you mentioned but thought I would try silent mode first. I will try it with the motor running in the morning before work. Do you think the first test result, getting voltage at the new pigtail with the ignition on and the switch on is valid to show that it isn't the PTO switch? I'm attaching photos of the battery area where that one fuse is located and one photo of the PTO clutch area in case that helps as well. I will post what happens when I try the jumper cable test with it running unless there's a reason not to proceed with that. Thanks again!

Frank

rbroug said:

black wires are ground, the other is 12 volt to clutch. with start switch on, pto switch on, jumper wire on seat. check 12 volt to neg. battery, machine frame and to the plug. should have 12 volts all 3 places on your meter. if you do check your clutch then, might have a bad ground. make sure your positive wire is going to your starter and the neg. goes to ground.

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Hi Rbroug,
Just a quick question on cable positions...where would each end of the jumper wire to the seat go? I pulled that plug and it has some very unusual looking prongs compared to the other connectors. With the start switch on and the PTO switch on but without the engine running, which is what I was mentioning to Ken, there is voltage at the pigtail that plugs onto the PTO clutch. Trying to understand the connections you're suggesting so I do it right the first time. Thanks!
Frank

Frank With your test results that tells me you do not need to run the motor that is good. Now when you got your 11.99v Where did you have the black test lead on your meter? This is what Rbroug was referring to. You need to have it on one on both of the black wires on the harness connectors. This will tell you the ground is (maybe) good going to the clutch. You may still need to clean it really good. If you have 12 volts and a good ground on the harness connector then we need to check the clutch. If this proves good then we need to check the resistance of the coil in the clutch with the ohm setting on your meter. I don't know what it should read. We will have to try and find this. Maybe someone reading this will chime in with the spec. Mean while check it if it is 0 Then we know it is open and no good.

Ken

bollingball said:

Frank With your test results that tells me you do not need to run the motor that is good. Now when you got your 11.99v Where did you have the black test lead on your meter? This is what Rbroug was referring to. You need to have it on one on both of the black wires on the harness connectors. This will tell you the ground is (maybe) good going to the clutch. You may still need to clean it really good. If you have 12 volts and a good ground on the harness connector then we need to check the clutch. If this proves good then we need to check the resistance of the coil in the clutch with the ohm setting on your meter. I don't know what it should read. We will have to try and find this. Maybe someone reading this will chime in with the spec. Mean while check it if it is 0 Then we know it is open and no good.

Ken

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Good morning Ken,
Late hours again yesterday but blessed to have a job. To answer your question, I was checking the voltage at the pigtail that comes from the new wiring harness to the PTO clutch. The yellow wire terminates in a crimped terminal on one side of the pigtail and the two black wires terminate in a crimped connector on the other side of the pigtail. There is a plastic divider between the two. I touched the black probe of my meter on the terminal with the black wires and the red probe on the terminal with the yellow wires. The connector is very clean because it's brand new and hasn't been used in a grass cutting mode yet unfortunately. A quick question on checking the resistance of the coil. Forgive my ignorance but I'm assuming the coil you refer to is the part onto which the pigtail plugs? If so, I'm also then assuming I follow the same basic procedure (ignition on, switch on, probes touching the respective negative and positive sides of the coil)? Sorry to be dense on this topic. As always, thanks for your time and help.

Frank

FHH said:

Good morning Ken,
Late hours again yesterday but blessed to have a job. To answer your question, I was checking the voltage at the pigtail that comes from the new wiring harness to the PTO clutch. The yellow wire terminates in a crimped terminal on one side of the pigtail and the two black wires terminate in a crimped connector on the other side of the pigtail. There is a plastic divider between the two. I touched the black probe of my meter on the terminal with the black wires and the red probe on the terminal with the yellow wires. The connector is very clean because it's brand new and hasn't been used in a grass cutting mode yet unfortunately. A quick question on checking the resistance of the coil. Forgive my ignorance but I'm assuming the coil you refer to is the part onto which the pigtail plugs? If so, I'm also then assuming I follow the same basic procedure (ignition on, switch on, probes touching the respective negative and positive sides of the coil)? Sorry to be dense on this topic. As always, thanks for your time and help.

Frank

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Frank NO NO you do not whant the power on when checking ohms you can burn your meter up or at the very least blow the fuse in it . There is a wire coil wound inside that clutch so it will be unpluged to test. It it acts like a magnet when the power is put to it and you have power. I hate to say it but it looks like yours may be shot But some of them have a adjustment on them. I don't know about yours You could take it off and take it to your JD dealer and have them check. First see if one of your ohm settings on your meter has a beeper on it when you touch the leads togeather it will beep. Most do have this. If yours does set it to this mode and touch the meter leads to the two prongs on the clutch where the new wire would plug in and see if it beeps if it does not beep it is shot. You will save a lot of money if you change it out but have them check it if you are not sure. That is all it can be if you have power and a ground. IMHO

Ken

you can do as i did, run wires off your pto to the battery it should click if it's good. if you lost the ground on the pto it wont work but you will have power to it. if you have a bad wire you can get 12v on a wire but not have the amps to run it.

rbroug said:

you can do as i did, run wires off your pto to the battery it should click if it's good. if you lost the ground on the pto it wont work but you will have power to it. if you have a bad wire you can get 12v on a wire but not have the amps to run it.

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Read post #7

bollingball said:

Read post #7

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Thanks for the info and for the safety reminder. Thanks also for saving my multimeter. I will probably need to elevate the front end of the mower somewhat because access to clearly see what I'm doing with that coiil isn't available from just a level position combined with my reading glasses. Just to be prepared for the worst, I will probably call the dealer today and see how much a PTO clutch is for this model. One other thought...since i still have that old pigtail that i cut from the main wiring harness, shouldn't I be able to remove the insulation from the black wires and yellow wire and plug it into the PTO clutch and then use the muiltimeter to test it IF I can verify that old pigtail is actually still workiing? Just a thought. Thanks again!

Frank