F525 mower (JD) only starts or runs if seat switch depressed.


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Old 05-05-21, 06:02 PM
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F525 mower (JD) only starts or runs if seat switch depressed.

I bought an F525.i noticed the seat switch was bypassed. I hooked it up and the machine would die is you hit any bumps. I figured the switch was getting too worn and sensitive so i ordered a new one. Same issue. So i dug in a bit. The mower should start without the switch depressed, if the parking brake is on and the pto is disengaged. It won't start unless the seat switch is depressed. Similarly, once running, you cannot dismount without it dieing. Again, with brake on and pto disengaged. All other safety functions seem to work properly. I've read several forums that dealt with a faulty neutral switch and would only run with brake engaged. This isn't my problem. As a side note, i own 3 f525s (long story, but 2 will be for sale). I mention this as i can verify proper functioning against these other 2. Any thoughts?
 

Last edited by ChadDIY; 05-05-21 at 08:25 PM. Reason: Typo
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Old 05-06-21, 03:20 AM
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You need a manual for the mower that has an electrical diagram to determine how the safety interlocks need to be wired. The safety interlock logic can be extracted from the electrical diagram if not explained in the manual. Some machines create a different safety interlock logic with the ignition switch being in the start or run positions.
 
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Old 05-06-21, 10:12 AM
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This is a highlighted ignition diagram.
 
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Old 05-06-21, 06:35 PM
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Thanks, Pjmax, for the elusive wiring schematic. Now if i was only smart enough to interpret it. I can decipher some of it. Since i have extra working machines i swapped parts. Specifically, i swapped brake/neutral switches. No change in behavior. Then i swapped the entire console that includes key switch, pto switch, (and odometer). No change. Finally, within the same mower, i swapped relays. Each time, i must have the seat depressed at all times to start and keep running. Does this mean it's a bad wire somewhere? There's other components, (starter, ignition module, coil, etc), but i don't think anything else can be to blame. From afar, all the wires look good and never tampered with. I don't want to cut open the wiring harnesses to look closer. One last thought, while disconnecting the keyswitch, i had it on RUN and accidentally shorted across the yellow/eed striped wire (assumed main power) and the solid purple wire. This hot wired it to turn over. But interesting enough, the seat switch wasn't depressed. Does this help diagnose for someone who understands the wiring better than me?

Thanks in advance for help. There's tons of great info and people on here.
 
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Old 05-06-21, 06:38 PM
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Oh, and all fuses are good too.
 
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Old 05-06-21, 11:38 PM
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Are there 2 wires or 4 going to the brake switch?
 
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Old 05-07-21, 12:18 PM
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4 to brake switch. 2 purple, 2 blue
 
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Old 05-07-21, 06:40 PM
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Try taking the connector off the brake switch and put a jumper wire from the one purple wire to the other and leave the other terminals open and give it a test.
 
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Old 05-08-21, 04:16 AM
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If there are 4 wires on the break switch, there are some wires missing on the above schematic. If the PUR and PUR/BLK connection (at what looks like S1) shown at the ignition switch was at the brake switch, there are only 3 wires at the break switch, not 4.
 
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Old 05-08-21, 08:42 AM
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Cheese, i jumped between the two purple wires in the brake switch and i experience the same behavior. It won't start without the operator on the seat, when the brake it depressed.
 
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Old 05-08-21, 08:45 AM
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I was wrong. There are actually 5 wires. A set of 3 purple in one connector and a set of 2 blue in the other connector. The switch itself has 4 prongs, as 2 of the purple wire are on 1 prong.


 

Last edited by ChadDIY; 05-08-21 at 08:51 AM. Reason: Correction
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Old 05-10-21, 07:37 AM
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Good morning. Anyone else have any ideas? I am sharing a previous similar thread, John Deere F525 start problem - DoItYourself.com Community Forums, in hopes it helps get some juices flowing.

On a side note, I am new to this forum, but just figured out how to change the email notification to instant, so i don't have to keep checking every couple hours to see if there is an update on this thread. :-)
 
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Old 05-20-21, 08:47 AM
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Checking in, hoping others have more ideas. I may try replacing the relays with one from a different mower. I'm just throwing darts now.
 
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Old 05-20-21, 09:27 AM
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did you try taking the switch off of one of the other mowers you have that you know works and try it on this one?
 
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Old 05-20-21, 10:09 AM
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yes. I swapped brake/neutral switches. No change in behavior. Then i swapped the entire console that includes key switch, pto switch, (and odometer). No change. Finally, within the same mower, i swapped relays. Each time, i must have the seat depressed at all times to start and keep running.
 
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Old 05-20-21, 11:21 AM
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so your probably not getting power to the ignition relay through the pto and brake switch would check for voltage through those switches and then at the relay the diagram shows a diode in that circuit if the diode was bad it would only work on the seat switch.
 
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Old 05-20-21, 12:39 PM
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Thanks, Alan. So make sure I have 12v coming to each sw (and exiting). I believe the switch always has 12v coming through, but switches where when open or closed. i do remember checking that it has continuity on one side with the other open, but then swaps when depressed.

Help me understand your last sentence. What behavior would you expect to see or not see if the diode is bad? Also, then please help me understand your rationale so i can learn a bit more.

I am pretty sure my meter has a diode function on it.

Lastly, I am not sure we are certain this is the correct diagram. See Beelzebob's note on 05-08-21, 11:16 AM
 
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Old 05-20-21, 01:15 PM
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not sure if the diagram is correct or not either, but assuming it is or atleast similar enough pin 86 of the ignition relay witch is what would provide power to the coil of the relay shows it can get power from 2 different sources one is the seat switch and the other 2 is the brake and pto switch the diagram shows a diode on that wire, not sure where it would actually be, but if you was not getting power from the brake and pto switch the relay would only work when the seat switch was powering the relay.
while you can check continuity of diodes with a meter and should show continuity in one direction and swap meter leads and not show continuity, would probably just do voltage checks through the brake and pto switches and at pin 86 first.
diodes only allow power to flow one way so if you do find a bad diode and replace it. just make sure your orient it so you have voltage at the relay if you install it backwards it would block voltage to the relay pretty simple to check with a test light or voltmeter.
 
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Old 05-20-21, 01:49 PM
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AM122590 that part seems to fit a lot of models you may have something like that in the wiring harness may want to google it for a picture.
 
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Old 05-20-21, 03:24 PM
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alan73 - Great information!!! i will check on this when i get home and give an update. I greatly appreciate this.
 
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Old 05-21-21, 07:52 AM
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alan73 - you are the man!!! Thank you so much for this info.

There's 4 diodes all about in the same place. It's hard to see and access this area to determine which one was part of which circuit. I just pulled all 4 and used my diode tester. One way they showed and open loop and the other it showed roughly .58 volts, except for one of the diodes that didn't have an open loop one direction. I grabbed a diode off a different mower and everything works as it should. I would have never figured this out without your help! Thanks again.

One more thought. Before I put my meter into diode mode, i tried the continuity mode. None of the diodes showed continuity in either direction, so without a diode function on your meter, I don't think you can rely on continuity testing.

I hope this thread is helpful to others in the future.
 
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Old 05-21-21, 10:16 AM
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probably depends on the meter but you should be able to read ohms on a diode on the direction that allows current through and may even have a reading the other direction also but it will be a very high resistance most auto ranging meters should give you a reading. where manual ones you may have to know what range to select to get a reading.
 
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Old 05-21-21, 07:17 PM
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Nice work alan73!




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