John Deere 5085E Stuck in 4wd

[OkieFarmer78]

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]

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

 

[OkieFarmer78]

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]

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]

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]

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]

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]

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]

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]

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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.

Fantastic information! This is what I needed.

Thank you!!!!

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