John Deere 5085E Stuck in 4wd

[OkieFarmer78]

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This is from a newer model 5090 or 5100. It looks like the signals are inputs into and out of the EHC unit. K15 is the relay for the EHC so that could be an issue but probably something is going on with the EHC.

Just an update. I've traced all the circuits. Switch circuit has 12v, and all wires going to the EHC were tested for continuity and then load tested. Same with the wire coming out of the EHC to the solenoid. The EHC is just not producing voltage to the solenoid. So, new EHC it is.

Thanks workinonit! Couldnt have done this without the schematic.

 

[workinonit]

Any time. Have you priced that controller?

 

[OkieFarmer78]

Any time. Have you priced that controller?

Yes. Looks like $1040.

 

[Harry in Ky]

I can't help but ask Did you try testing the solenoid with 12 volts? If so, did the 4WD disengage?

 

[OkieFarmer78]

I actually Purchaed a new solenoid, as I thought that was the issue at first. I’ve tested the solenoid, and it’s good. I haven’t tried manually powering the solenoid while it’s in the tractor to see if it will physically come out of 4wd, since I was getting 0 volts to the solenoid - it told me the issue was upstream of the solenoid.

Further update - another EHC didn’t fix it. Still no voltage from the EHC to the solenoid. So thinking there must be another circuit tied in somewhere. Spent some serious time going over It all with then JD field tech. He’s stumped as well. More to come….

 

[workinonit]

Is the K15 relay energizing?

 

[OkieFarmer78]

Is the K15 relay energizing?

Yes. K15 is. And fuse # 20 is good. Removing either of these (the relay or the fuse) cuts the 12v power to the 4wd switch.

 

[Harry in Ky]

I actually Purchaed a new solenoid, as I thought that was the issue at first. I’ve tested the solenoid, and it’s good. I haven’t tried manually powering the solenoid while it’s in the tractor to see if it will physically come out of 4wd, since I was getting 0 volts to the solenoid - it told me the issue was upstream of the solenoid.

Further update - another EHC didn’t fix it. Still no voltage from the EHC to the solenoid. So thinking there must be another circuit tied in somewhere. Spent some serious time going over It all with then JD field tech. He’s stumped as well. More to come….

That's precisely why I would try supplying 12 volts to the coil to see if it actually works. If it does, then you know you have a working switch and a working solenoid. What's in between is up to you. You can keep buying nonreturnable parts, maybe get it right, or get creative. Your money, your choice.

 

[workinonit]

Doing that is obviously something that he could try but until he gets 12 volts to the solenoid he knows it's not going to work. My guess now is you have something going on in the wiring harness. Or there's something going on in the controllers.

 

[OkieFarmer78]

That's precisely why I would try supplying 12 volts to the coil to see if it actually works. If it does, then you know you have a working switch and a working solenoid. What's in between is up to you. You can keep buying nonreturnable parts, maybe get it right, or get creative. Your money, your choice.

I’ve already tested the switch, and the solenoid. They are both fine. Yes, applying outside voltage to the solenoid would physically put the tractor in 2wd. But that’s not what I’m after. There’s a wiring / controller issue here, and I want to fix it right, and find out why the solenoid is not getting voltage though the factory harness.