John Deere 5085E Stuck in 4wd

OkieFarmer78 · Feb 8, 2023

Ok. I'm Stumped on this one...

I have a 2017 John Deere 5085E. The 4wd light on the dash, is on constantly. (Was like this when I purchased it). Regardless of where I position the switch, it will not disengage. I realize that 4wd is the default for these tractors, and that the solenoid requires power to keep the tractor in 2wd. I've checked the obvious - no blown fuses. I have power at the 4wd switch on the console, and tested the switch (its good). I have however no power to the solenoid. The plug to the solenoid is 2 wires. I've tested continuity on the ground side of the plug, and its fine. However I cant seem to trace the hot side once it goes into the cab. Also read where there is a controller for the dash light..?

I've had no luck on a wiring diagram/schematic. Curious if anyone else has fought this same thing? Assuming the wiring is probably the same for the 5085/5090E/5100E?

MTGreen · Feb 8, 2023

The light's on but are you sure the tractor is physically in four wheel drive?

OkieFarmer78 · Feb 8, 2023

Correct. Lights on the dash. No Power going to the solenoid. Tractor is most certainly in four wheel drive, as you can tell when turning, its pulling/pushing like it should in four wheel.

zzvyb6 · Feb 8, 2023

Does it actually drop out of 4wd but the light stays on ?
Can you hotwire the clutch which disengages the 4wd ?
Is it actually in 4wd, or locked into 2wd ?
Are the tires so mismatched that the clutch won't release because of rpm clash ?

If you have a loader, raise the front axle off the ground with the bucket on the ground like a sled and see what the situation is.

OkieFarmer78 · Feb 8, 2023

zzvyb6 said:
Does it actually drop out of 4wd but the light stays on ? No. Moving the switch does not pull it out of 4wd, regardless.
Can you hotwire the clutch which disengages the 4wd ? This is one of my next moves - to put 12v to the solenoid, but my understanding is, if I provide power outside of the cuircut, the dash light will remain on.
Is it actually in 4wd, or locked into 2wd ? Tractor is stuck in 4wd. I have the switch in the 2wd position. Moving it from 2wd to 4wd does nothing.
Are the tires so mismatched that the clutch won't release because of rpm clash ? Negative.

If you have a loader, raise the front axle off the ground with the bucket on the ground like a sled and see what the situation is. Front tires rotate like the should in 4wd.

LouNY · Feb 8, 2023

I would expect that you have a relay that the switch should be controlling.
That relay is likely a multiple pole which would turn off the light and activate the 4wd solenoid at the same time.

Harry in Ky · Feb 8, 2023

I'm betting there's more than just "a relay". I suspect there's a computer somewhere as well, brake pedal switches, the 2/4 WD switch, and possibly even more. Just because you turn the switch off and on doesn't mean you're actually sending signal to the solenoid valve.

OkieFarmer78 · Feb 9, 2023

Harry in Ky said:
I'm betting there's more than just "a relay". I suspect there's a computer somewhere as well, brake pedal switches, the 2/4 WD switch, and possibly even more. Just because you turn the switch off and on doesn't mean you're actually sending signal to the solenoid valve.

Right. Thats what I'm thinking. Trying to come up with a wiring diagram.... :/

workinonit · Feb 9, 2023

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.

OkieFarmer78 · Feb 9, 2023

workinonit said:
View attachment 783148 View attachment 783149 View attachment 783150 View attachment 783151 View attachment 783152

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.

Fantastic information! This is what I needed.

Thank you!!!!

Will post back up the 'fix' when I find it.

OkieFarmer78 · Feb 10, 2023

workinonit said:
View attachment 783148 View attachment 783149 View attachment 783150 View attachment 783151 View attachment 783152

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 · Feb 10, 2023

Any time. Have you priced that controller?

OkieFarmer78 · Feb 10, 2023

workinonit said:
Any time. Have you priced that controller?

Yes. Looks like $1040.

Harry in Ky · Feb 10, 2023

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

OkieFarmer78 · Feb 10, 2023

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 · Feb 10, 2023

Is the K15 relay energizing?

OkieFarmer78 · Feb 10, 2023

workinonit said:
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 · Feb 10, 2023

OkieFarmer78 said:
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 · Feb 11, 2023

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 · Feb 11, 2023

Harry in Ky said:
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.