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Discussion Starter · #1 ·
As the title says my 318 cuts off like the key was turned when I flip the PTO switch. The previous owner deleted the seat switch (I do plan on re connecting when this issue is solved), so I don't think that's the issue. It starts and moves just fine. The issue came up when I was out mulching leaves. It seemed to work great until I turned the PTO off then tried to turn it back on to no avail. I took the seat pan off and looked for splices and only found one (see pic below).
Circuit component Electrical wiring Hardware programmer Finger Electronic engineering
that green wire runs to a aftermarket switch installed in the dash. The switch also has a wire running to the battery with a 20A fuse in the line. The previous owner said it was installed as a "cutoff switch". It has to be turned on for the tractor to start. I attempted to remove it, but the tractor won't start without it. I'd like to get rid of it either way, but don't know if it's the source of my issue due to the fact that the PTO was running fine before with the switch installed. Other issues that might help- the battery light stays on, and sometimes the tractor won't shut off with the ignition I have to use the previously mentioned switch to shut it down. I'm absolutely stumped. Sorry for the long post and thanks for your help/time.
 

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I use scissors! Twice a week.
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It sounds like the P.O. hacked up the wiring harness just to make it work, rather than fixing whatever was the actual problem. I would suggest finding/getting the wiring diagram and then working on one electrical issue at a time (by either fixing and/or restoring a given circuit to it's original configuration). Tedious, but it sounds like this is a new-to-you tractor that you want to use for some time, and doing it gets the tractor back to a known, reliable electrical system.
 

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Discussion Starter · #5 ·
It sounds like the P.O. hacked up the wiring harness just to make it work, rather than fixing whatever was the actual problem. I would suggest finding/getting the wiring diagram and then working on one electrical issue at a time (by either fixing and/or restoring a given circuit to it's original configuration). Tedious, but it sounds like this is a new-to-you tractor that you want to use for some time, and doing it gets the tractor back to a known, reliable electrical system.
I totally agree that the tractor needs to be reworked. Unfortunately electrical represents the largest gap in my knowledge, but fortunately I'm willing to learn. Should I tear the tractor down to the frame and start there? Where's the best place to start something like that in your opinion?
 

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I use scissors! Twice a week.
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I would
-get the wiring diagram for the tractor
-any places where the P.O. obviously has modified the harness, compare it with the wiring diagram and restore it to how the wiring diagram shows (and I would spend the time/money to retain the correct wire colors, as it makes things easier in the future),
-work through getting the engine starting, then running, then pto, then lights/any other electrical stuff

You can do it all with a cheap multimeter, but I would recommend something like the Autel Powerscan PS100 for doing this, as I find it MUCH easier to see what's getting power/ground/no connection/what voltage is pressent with it, as well as providing power or ground to a point for testing (as well as other stuff), and doing it one-handed vs trying to hold two probes to connectors, then trying to work a button/switch...

Alternately, you might see if JD/someone else is selling a wiring harness for your tractor, and then just swap it in.
 

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Kish JD 318/420/430
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The wiring diagrams and diagnostic are in the TM1590. Open it up and printout the sections for PTO operation and ignition system.
 

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Discussion Starter · #8 ·
I would
-get the wiring diagram for the tractor
-any places where the P.O. obviously has modified the harness, compare it with the wiring diagram and restore it to how the wiring diagram shows (and I would spend the time/money to retain the correct wire colors, as it makes things easier in the future),
-work through getting the engine starting, then running, then pto, then lights/any other electrical stuff

You can do it all with a cheap multimeter, but I would recommend something like the Autel Powerscan PS100 for doing this, as I find it MUCH easier to see what's getting power/ground/no connection/what voltage is pressent with it, as well as providing power or ground to a point for testing (as well as other stuff), and doing it one-handed vs trying to hold two probes to connectors, then trying to work a button/switch...

Alternately, you might see if JD/someone else is selling a wiring harness for your tractor, and then just swap it in.
Really appreciate that step by step, Dave. I'll start looking into it this weekend.
 

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Discussion Starter · #9 ·
So I've taken a look at the wiring diagram and it looks like that loop that was hacked into is the connector for the rear PTO which my 318 does not have. Just to get me started in the right direction does anyone know why the P.O. would have spliced power into that loop? From what I see in the diagram I don't think it would normally have power running to it directly. I feel like If I can find that original power source that the P.O. either couldn't diagnose or didn't care to I can start to find the source of this and several other problems. Thanks!
 

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Discussion Starter · #10 ·
Partial success!! I deleted the "cutoff switch" and the tractor starts and stops as it ahould. It doesn't die when I switch the PTO on, but the PTO still doesn't run. After following through the repair manual I came to the conclusion that "the purple wire between jumper connector and PTO switch is open" and the solution is to replace the wire. Does this make sense to you all?
 

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I know you are in the right spot--I had the same problem with the PTO and it would not work ---I had a bad seat switch--so that puts you right in there somewhat where the problem is. ------ Bad connectors also in the PTO area. ----- cut wire maybe. Good Luck
 

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Partial success!! I deleted the "cutoff switch" and the tractor starts and stops as it ahould. It doesn't die when I switch the PTO on, but the PTO still doesn't run. After following through the repair manual I came to the conclusion that "the purple wire between jumper connector and PTO switch is open" and the solution is to replace the wire. Does this make sense to you all?
Sounds like you found it.
 

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Just throwing this in as a quick "get lucky"..
If you remove the 4x6" cover on the right side of the pedestal (or go under the battery tray?) there is a multi-pin connector that often gets bad connections in it. That is where my PTO quit working. As I jiggled that connector, I could get the PTO to kick in and out. You might want to check that before you go too far.
 

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Discussion Starter · #16 ·
Just throwing this in as a quick "get lucky"..
If you remove the 4x6" cover on the right side of the pedestal (or go under the battery tray?) there is a multi-pin connector that often gets bad connections in it. That is where my PTO quit working. As I jiggled that connector, I could get the PTO to kick in and out. You might want to check that before you go too far.
CantKeepUp,

Are you talking about the pigtail that comes out of the TDCM? If so that's really a coincidence. I literally had the same thought at about 11pm last night. Got up off the couch to go down and take a look and that connection was just crammed with 30+ years of dust and dirt. It was close to impossible to pull apart. I plan on cleaning it up today. Thanks for the heads up!
 
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