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John Deere 997 Seat Safety Not Working

#1

jshep1102

jshep1102

Hi guys,
I'm working on a John Deere 997 Z-Trak for a friend and I'm trying to get the seat safety switch to work. I think it may be an early 2000's model (ID# DM997SC020068).

Complaint - mower will not cut off while mower deck is engaged and you lift your butt out of the seat.

Things I've done/found:
1. Seat safety switch confirmed to close when switch depressed and open when nobody in the seat.
2. Mower start and runs/mows normally otherwise.
3. neutral safeties both confirmed to work: i.e. mower won't start with either lever out of neutral position (don't think it has anything to do with the problem but I checked it anyways).
4. Brake safety works as expected (again, don't think it has anything to do with the problem but I checked it anyways)
5. Previous owner had a jumper piggybacked from red wire of seat timer delay module running to the red wire on shutoff solenoid valve. No idea why it was installed so I disconnected it and everything is still acting the same.
6. Seat timer delay module has zero VDC on red wire with key off and 12+VDC with key in run position. (4 pin plug associated with this module)
7. I swapped the Start relay (7th of 10 relays) with the Seat relay (9th of 10 relays) to see if it was a bad seat relay. No change. Mower still starts and seat switch still not working.

Could it just be a bad seat delay module? Thanks in advance for any help you can provide.
Jerry


#2

jshep1102

jshep1102

Does anyone have a good electrical schematic I can get? I have the Owners Manual and an Operators Manual but neither of them have a schematic.


#3

K

Kenbu

Similar thread on another forum https://www.greentractortalk.com/threads/z997-safety-switch-problems.229060/


#4

StarTech

StarTech

If this is a Z997R then you need to get a copy of the TM132819 technical manual which would the schematic. That is if you can afford $15.

But most likely ECU has failed. I seen a lot problems on other JD units that uses these control modules. Most I was able to bypasses on but this seat switch circuit can't simply be bypass to get the system to work as intended.


#5

jshep1102

jshep1102

Kenbu said:
Similar thread on another forum https://www.greentractortalk.com/threads/z997-safety-switch-problems.229060/
Click to expand...
I saw that thread but it's addressing a problem a little different than the one I'm having. It also has a different style of time delay module. It has 4 pins in a 2x2 configuration. Mine is a 4 pin in a flat configuration. Thanks for the response though.


#6

jshep1102

jshep1102

StarTech said:
If this is a Z997R then you need to get a copy of the TM132819 technical manual which would the schematic. That is if you can afford $15.

But most likely ECU has failed. I seen a lot problems on other JD units that uses these control modules. Most I was able to bypasses on but this seat switch circuit can't simply be bypass to get the system to work as intended.
Click to expand...

Thanks StarTech. I can't tell if this mower is the "R" version of the 997. No labels anywhere show an "R" after the 997. For $15, I'd gladly get the tech manual. Where's the best place to get it?
20251023_181901.jpg20251024_092506.jpg


#7

A

Auto Doc's

jshep1102 said:
Thanks StarTech. I can't tell if this mower is the "R" version of the 997. No labels anywhere show an "R" after the 997. For $15, I'd gladly get the tech manual. Where's the best place to get it?
View attachment 72120View attachment 72121
Click to expand...
Hello J.,

Remove the screws from the right side (has seated on the machine), lift up the control panel and look for a red or black square "box" plug-in interlock diode. I recently had a JD 757 zero turn that shorted out the seat harness and popped the diode. Now it does not have the diode to interfere with the operations.

If this model has the time delay control module (magic box) disregard searching for the diode mentioned.


#8

StarTech

StarTech

2006 Model (Serial No. DM997SC020001-030100)

IPL don't show an ECU instead a mess of relays so this is not a "R" series. Darn it. Have to contact JD for what is the correct service manual PN.


#9

jshep1102

jshep1102

StarTech said:
2006 Model (Serial No. DM997SC020001-030100)

IPL don't show an ECU instead a mess of relays so this is not a "R" series. Darn it. Have to contact JD for what is the correct service manual PN.
Click to expand...
Thanks Star
Well, that explains why I couldn't find an ECU anywhere on that tractor. 10 relays in a row above the engine.


#10

jshep1102

jshep1102

Auto Doc's said:
Hello J.,

Remove the screws from the right side (has seated on the machine), lift up the control panel and look for a red or black square "box" plug-in interlock diode. I recently had a JD 757 zero turn that shorted out the seat harness and popped the diode. Now it does not have the diode to interfere with the operations.

If this model has the time delay control module (magic box) disregard searching for the diode mentioned.
Click to expand...
AutoDoc,
It has a 4 pin connector for the seat control module like the one shown in the attachment. It that the magic box you were thinking about?

Attachments





#11

A

Auto Doc's

Go to the link Kenbu sent you and scroll down the page, "old cajun" has it all laid out


#12

jshep1102

jshep1102

Auto Doc's said:
Go to the link Kenbu sent you and scroll down the page, "old cajun" has it all laid out
Click to expand...
The screenshots of ways to check the timer module are for a type different than mine. It shows a square 4 pin plug in a 2x2 configuration. Mine is a 1x4 flat configuration. I attached pics of the 2 different styles I've found.
I was wishing Kenbu's pic showed wire colors so I could check to see if mine had the same colors.

Attachments







#13

StarTech

StarTech

Here is a hint from the 777, 797 that uses the same delay module.

1. A delay module might be installed in place of wire 477 yellow. The
delay module prevents errant engine shut-off caused by the seat switch
being momentarily disengaged due to operating on very rough terrain.
1761739886516.png
if this is correct and the Z997 is using the wiring numbers then you can remove the delay module and install a test jumper to see if the module is the problem area. Just make sure you jump the right two wires. There will be 12v on one of the wires which what activates the module which in turn activates the magneto stop and keeps the fuel solenoid active during about a 2 sec delay. This circuit controls the magneto stop relay and the fuel solenoid on the 777, 797 mower.

But as I said I don't have the SM for the International version of the Z997 at hand. So this is just a guess.


#14

jshep1102

jshep1102

StarTech said:
Here is a hint from the 777, 797 that uses the same delay module.

1. A delay module might be installed in place of wire 477 yellow. The
delay module prevents errant engine shut-off caused by the seat switch
being momentarily disengaged due to operating on very rough terrain.
View attachment 72133
if this is correct and the Z997 is using the wiring numbers then you can remove the delay module and install a test jumper to see if the module is the problem area. Just make sure you jump the right two wires. There will be 12v on one of the wires which what activates the module which in turn activates the magneto stop and keeps the fuel solenoid active during about a 2 sec delay. This circuit controls the magneto stop relay and the fuel solenoid on the 777, 797 mower.

But as I said I don't have the SM for the International version of the Z997 at hand. So this is just a guess.
Click to expand...
If it is a failed delay module, it has failed in the "energized" condition and is keeping the fuel solenoid and/or magneto stop from killing the engine when the operator leaves the seat for >2sec. It's a rainy day today so I'll have to do some more testing tomorrow afternoon when the rain is supposed to stop. Thanks for the help Star!


#15

M

masterchief davis

jshep1102 said:
Hi guys,
I'm working on a John Deere 997 Z-Trak for a friend and I'm trying to get the seat safety switch to work. I think it may be an early 2000's model (ID# DM997SC020068).

Complaint - mower will not cut off while mower deck is engaged and you lift your butt out of the seat.

Things I've done/found:
1. Seat safety switch confirmed to close when switch depressed and open when nobody in the seat.
2. Mower start and runs/mows normally otherwise.
3. neutral safeties both confirmed to work: i.e. mower won't start with either lever out of neutral position (don't think it has anything to do with the problem but I checked it anyways).
4. Brake safety works as expected (again, don't think it has anything to do with the problem but I checked it anyways)
5. Previous owner had a jumper piggybacked from red wire of seat timer delay module running to the red wire on shutoff solenoid valve. No idea why it was installed so I disconnected it and everything is still acting the same.
6. Seat timer delay module has zero VDC on red wire with key off and 12+VDC with key in run position. (4 pin plug associated with this module)
7. I swapped the Start relay (7th of 10 relays) with the Seat relay (9th of 10 relays) to see if it was a bad seat relay. No change. Mower still starts and seat switch still not working.

Could it just be a bad seat delay module? Thanks in advance for any help you can provide.
Jerry
Click to expand...
its probably the buttons under the seat not adjusted for making contact with seat raised try pushing the buttons with seat raised,


#16

StarTech

StarTech

masterchief davis said:
its probably the buttons under the seat not adjusted for making contact with seat raised try pushing the buttons with seat raised,
Click to expand...
This system uses 12 vdc thru the seat switch and the time delay to activate a relay and the fuel solenoid so the engine will start and run. It must become an open circuit to disengage the relay and to deactivate the fuel solenoid. This means the seat switch is NO and not a NC switch.


#17

jshep1102

jshep1102

StarTech said:
This system uses 12 vdc thru the seat switch and the time delay to activate a relay and the fuel solenoid so the engine will start and run. It must become an open circuit to disengage the relay and to deactivate the fuel solenoid. This means the seat switch is NO and not a NC switch.
Click to expand...
Correct, switch is open with nobody in the seat. It closes with relatively light pressure on the seat so i'm confident this switch is not the issue.
I stopped at 2 local shops today trying to find an electrical schematic to aid in troubleshooting but neither could access it. The closest john deere dealer is over an hour away.


#18

StarTech

StarTech

jshep1102 said:
Correct, switch is open with nobody in the seat. It closes with relatively light pressure on the seat so i'm confident this switch is not the issue.
I stopped at 2 local shops today trying to find an electrical schematic to aid in troubleshooting but neither could access it. The closest john deere dealer is over an hour away.
Click to expand...
I emailed one of my JD dealers to see if I can get a diagram or at least the correct tech manual PN so I can search for it on the net.


#19

jshep1102

jshep1102

OK, the rain finally stopped and I got to dig a little deeper. I found a picture of a 2x2 pin configuration delay module that showed wire colors and I checked resistance reading that Kenbu posted on my 1x4 pin configuration delay module. They were very similar readings as shown in the attached pic so I don't think I have a bad delay module. More digging ensued.
Aha!, I found some more wire modification shenanigans put in place by a previous owner. Under the control panel, i found another jumper that picked up power off of one lead coming from to the ignition switch and fed it to a solenoid on the hydraulics pump. The other leg of the plug at the solenoid was jumpered to a wire on the PTO switch. Again, no idea why someone put this and the other jumper (delay module to fuel cutoff solenoid) in place. Not sure if the previous owner was a genius fixing a problem I haven't found yet or a hack just finding power/ground somewhere and using it willy-nilly to get something to work rather than fixing what was really wrong. Use of these blue piggyback splice connectors probably eliminates the genius probability.
I think I found the service manual on Ebay for this mower that should have schematics I can use to figure it out. I'll write the seller to confirm it covers my particular mower.
The saga continues...!

Attachments









#20

jshep1102

jshep1102

StarTech said:
I emailed one of my JD dealers to see if I can get a diagram or at least the correct tech manual PN so I can search for it on the net.
Click to expand...
oops, didn't see your post before I ordered the ebay service manual. It is TM2259 and it says it covers s/n 010001- up. It was only $25 (digital copy) so I'm not out much if I ordered the wrong one. Thanks for all your help.


#21

StarTech

StarTech

That's okay as I will DL a copy of the TM2259 for my shop too since I don't have that copy here. GFP hasn't responded to me yet.

Update

And I just looked over that TM2259 and it appears to be the correct manual. Tnx for the TM PN.

Partial seat switch circuit diagram. Boy I haven't seen a PNP transistor used in a long time.
1761856065184.png
Remove the module and temporary jumper green wires 640 and 641 together. This will bypass the time delay module for test purposes.


#22

A

Auto Doc's

jshep1102 said:
OK, the rain finally stopped and I got to dig a little deeper. I found a picture of a 2x2 pin configuration delay module that showed wire colors and I checked resistance reading that Kenbu posted on my 1x4 pin configuration delay module. They were very similar readings as shown in the attached pic so I don't think I have a bad delay module. More digging ensued.
Aha!, I found some more wire modification shenanigans put in place by a previous owner. Under the control panel, i found another jumper that picked up power off of one lead coming from to the ignition switch and fed it to a solenoid on the hydraulics pump. The other leg of the plug at the solenoid was jumpered to a wire on the PTO switch. Again, no idea why someone put this and the other jumper (delay module to fuel cutoff solenoid) in place. Not sure if the previous owner was a genius fixing a problem I haven't found yet or a hack just finding power/ground somewhere and using it willy-nilly to get something to work rather than fixing what was really wrong. Use of these blue piggyback splice connectors probably eliminates the genius probability.
I think I found the service manual on Ebay for this mower that should have schematics I can use to figure it out. I'll write the seller to confirm it covers my particular mower.
The saga continues...!
Click to expand...
Hello J.,

When I see tap splices like that, it spells "rednecks and beer" around my area. Those things should be outlawed. Small utility trailer companies use them by the bags full, they are nothing but trouble.

Your test measurements are not terribly off, so I suggest you correct all the creative wire passing attempts and restore it back to original before you condemn the delay module.

Marine butt slices with sealant in them are ideal for this kind of repair. Wiring can be tedious, but if done correctly, it will last you for many years.

Last item I will mention is to remove all the cable ties that appear to be overtightened. That causes broken wire strands inside the wire insulation.


#23

jshep1102

jshep1102

StarTech said:
That's okay as I will DL a copy of the TM2259 for my shop too since I don't have that copy here. GFP hasn't responded to me yet.

Update

And I just looked over that TM2259 and it appears to be the correct manual. Tnx for the TM PN.

Partial seat switch circuit diagram. Boy I haven't seen a PNP transistor used in a long time.
View attachment 72153
Remove the module and temporary jumper green wires 640 and 641 together. This will bypass the time delay module for test purposes.
Click to expand...
OK, I've run out of daylight but we're getting closer (I think). Still weird response, this is what I have:
1. With key in "RUN" position, I have 12+VDC on yellow 509 at seat delay module (expected)
2. With key in "RUN", I do not have any voltage at yellow 510 at the seat switch (unexpected)
3. With key in "RUN", I do not have any voltage on green 641 at K2 seat relay (Unexpected)
4. However, in "RUN", I do have voltage at green 640 at delay module (unexpected) even with the seat switch unplugged. Obviously, i'm picking up 12V on green 640 somewhere but I haven't found out where yet. I'm guessing somewhere, the previous owner jumped 510 yellow to 640 green
5. I have a 5th wire attached to 87A terminal on the seat relay. Is it possible this partial schematic isn't applicable to my mower.

I like a good electrical troubleshooting problem. I got one here for sure. Thanks for hanging in there with me.


#24

StarTech

StarTech

sorry i posted an earlier partial for before SN 020001

this is for the (S.N. 020001-050000) that 5th wire should be a pink wire [658].
1761867964857.png


#25

StarTech

StarTech

Sorry the attached is not super clear but even the service manual image are not very clear. But I spliced together multiple [6 pages] to give overall idea how this nightmare wiring is done.

Attachments





#26

jshep1102

jshep1102

StarTech said:
Sorry the attached is not super clear but even the service manual image are not very clear. But I spliced together multiple [6 pages] to give overall idea how this nightmare wiring is done.
Click to expand...
Perfect!!! Thanks so much. It'll take me a little time to decipher this but step one is to figure out why seat switch 510 yellow has no power. It seems it has to be a broken wire somewhere because 509 yellow has power at the seat delay module. Just gotta find the ghost or goblin in this machine here on Halloween!


#27

A

Auto Doc's

If I read the 6-page diagram correctly the machine has to be running for the alternator to power that 510 circuit to the seat switch. I could not enlarge the diagram well enough on my laptop.


#28

jshep1102

jshep1102

Auto Doc's said:
If I read the 6-page diagram correctly the machine has to be running for the alternator to power that 510 circuit to the seat switch. I could not enlarge the diagram well enough on my laptop.
Click to expand...
I thought the same thing when I saw the schematic but that yellow 510 is hot in the key ON position. It must provide field excitation to the alternator.


#29

jshep1102

jshep1102

Good News/Bad News
Good news - I found the problem w/ the seat safety switch not getting power. The previous owner was very tricky and spliced green and yellow wires going to the seat switch and buried the splice WAY up the factory loom that protects the wires. After several hours of tracing power through the circuits, I knew the yellow wire to the seat switch was compromised but the loom still looked like factory installation. Eventually, I pulled that wire/loom and found the latest shenanigans. Seat safety now kills the mower if you get out of the seat while deck is engaged. Pics attached.

Bad news - I disabled rogue jumper #2 (from PTO switch to PTO solenoid) and plugged in the original wires. The PTO won't engage now (kinda figured that would happen because I didn't find any problems yet that would have caused the previous owner to install it). The funny part now (I can't make this stuff up) is with the PTO switch OFF, getting out of the seat causes the deck to engage. That doesn't sound safe. :) More schematic studying and wiring tracing to follow.

Thanks so much for all your help getting me this far. The 6 page schematic allowed me to test a LOT of components to narrow it down to the actual problem. I'll use the schematic to solve the newest problem too.

Attachments







#30

A

Auto Doc's

jshep1102 said:
I thought the same thing when I saw the schematic but that yellow 510 is hot in the key ON position. It must provide field excitation to the alternator.
Click to expand...
Thanks for the updates as you are progressing. I see so many smaller units, that I forgot this actually has a real alternator.


#31

jshep1102

jshep1102

Oh, the sweet taste of success. I figured it out!! I had a bad connection in the plug (circled in red on the pic) at the brake switch that prevented power from being fed to the PTO clutch and the fuel cutoff solenoid (green traces in the pic) when the brake was disengaged. The previous owner obviously didn't find this problem so he installed 2 jumpers to put power in places that fed these components. With the restoration of the leads going to the seat safety switch I fixed a couple of days ago, all wiring is now back to factory configuration and the mower works as designed.

Thanks to StarTech and Auto Docs for providing the schematic and some guidance in the troubleshooting. Without that schematic, I could have never developed a logical plan to troubleshoot. You guys (and this site) rock!

Now that it's fixed, the 700+ page service manual should arrive tomorrow. Money well spent for any issues going forward.

Attachments





#32

A

Auto Doc's

jshep1102 said:
Oh, the sweet taste of success. I figured it out!! I had a bad connection in the plug (circled in red on the pic) at the brake switch that prevented power from being fed to the PTO clutch and the fuel cutoff solenoid (green traces in the pic) when the brake was disengaged. The previous owner obviously didn't find this problem so he installed 2 jumpers to put power in places that fed these components. With the restoration of the leads going to the seat safety switch I fixed a couple of days ago, all wiring is now back to factory configuration and the mower works as designed.

Thanks to StarTech and Auto Docs for providing the schematic and some guidance in the troubleshooting. Without that schematic, I could have never developed a logical plan to troubleshoot. You guys (and this site) rock!

Now that it's fixed, the 700+ page service manual should arrive tomorrow. Money well spent for any issues going forward.
Click to expand...
Hello J.,

Thanks for the resolution and closure. We see way too many disappear, because they actually fixed them, or got frustrated and gave up.


#33

jshep1102

jshep1102

StarTech said:
That's okay as I will DL a copy of the TM2259 for my shop too since I don't have that copy here. GFP hasn't responded to me yet.
Click to expand...
StarTech, I got the service manual for this mower now. Is there way to Direct Message you on this site?


#34

StarTech

StarTech

jshep1102 said:
StarTech, I got the service manual for this mower now. Is there way to Direct Message you on this site?
Click to expand...
Sorry the management chewed my backside out about using PMs so I had to disable them. There was propriety info that I was sharing only with the poster that I couldn't publicly disclose. That info was on a need to know basis. Not every Tom, Dick, and Harry on the web needed to have access to that info. And companies like Stihl have shut down some sites for releasing their dealer only info publicly.

Please understand....


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