JD Tractor Electrical

[Dale_W]

STX38 Product ID: M00STXH276818
Kohler Command 13
family SKH398U1G2RB
model CV13S
spec 21509
serial 2525111412

Here's what happens: Put your foot on brake, set choke, engine starts and runs fine. Select a gear, let foot off brake, engine dies. Seems like a safety switch, not mechanical binding.

So I look for tell-tale signs of Bubba. Only found one. The seat safety switch was taped into the pushed-in position. I remove tape, and check switch with ohm meter. The switch is normally closed, and works fine. However, with switch installed, (open or closed), or switch not installed, symptoms are the same: starts fine, dies when you let off the brake.

I did a quick look with a flashlight for other signs of Bubba, or bad connections, or wires worn thru, but everything seems ok. Clearly, everything is not ok.

Where should I start looking? Also, I checked that plug for the seat switch with a DC volt meter. No juice when starting or running.

I have just started looking at the JD site for wire diagrams, but I thought I ask here.

Also, may or may not be related. When I pull the knob for the PTO, nothing happens. I did not yet check for voltage going to the electric clutch. Should have done that last night.

Thanks

Dale

[KE4AVB]

Physically disconnect one of the wire at the seat connector as it has a shorting strip built-in.

Plus check your inbox a SM download link.

[Dale_W]

Thank you for that link, KEV. That will be a HUGE help.
Sigh. Silly work won't let me access, I will have to do that from home.
I get it, we don't want to be the next Target or Equifax with a security breach. I'm happy I can still get to PPETEN from work.

There are two white wires going to one side of the connector, and one black that I can trace to ground.

Are you saying I can cut either of the white wires? Sorry for being feebleminded.. Maybe when I can get at that manual I'll understand.

[38racing]

manual I'm glancing at has yel brn pnk on seat switch but I don't see the path to brake yet. I would think that if you remove the one to ground that be a good test. have you traced a wire from brake switch to seat switch?
update: so now I see another page with seat switch with black to ground and two blk/wht. one from pto switch and one from brake switch

[Dale_W]

38, well isn't that interesting since the PTO isn't working either!

When you look at the diagram, can you tell should the switch be normally open or normally closed? Who knows what Bubba did in there!

[38racing]

you can get the manual here.
www.manualsdir.com/manuals/600879/john-deere-stx38.html

[hanz63]

The first thing I do on these is to check the engine mounting bolts. One secures a ground wire. Notorious for engine mounting bolts to loosen and drop out, sometimes allowing the engine to tear the harness at the rear of the engine.

[Dale_W]

Follow up.
Hanz, last night I looked for missing engine mounting bolts. One was missing, but not the one used to ground the wire harness.

KE4AVB, I was able to easily pull the ground wire out of the plug for the seat safety switch. Both the PTO and Brake leave the engine running now.
Upon closer inspection I could see that Bubba had somehow mangled the little grounding strip in the plug, so the circuit was grounded, even with the switch plugged in.
But wait, there's more. Bubba also threw away the seat switch mounting plate. I will have to find a replacement. I want to return the tractor with the seat switch working.

Thank you very much for help. You guys a great resource.

Dale