John Deere 3720 Wiring schematic

Forrest1357 · Apr 26, 2014

If anyone could please help me out with a wiring schematic for a John Deere 3720. I have someone trying to help me with the wiring to the forward/reverse and am in desperate need for this help. I have been unable to move F/R for a week and this mechanic is trying to troubleshoot for me.:confused2:

Oldtink · Apr 27, 2014

A little more info might be helpful. What year? Cab or OS? eHydro or power reverser?
Could be something as simple as a seat switch.

arlen4720 · Apr 27, 2014

What error codes is it throwing?

Forrest13 · Apr 29, 2014

arlen4720 said:
What error codes is it throwing?

I get a error 12. I however had a mechanic take a look and he said he's only getting 1.6 volts out of the HST controller. He said he really needs the schematics. I'm willing to pay for a download but can't find it on line

Forrest13 · Apr 29, 2014

Forrest13 said:
I get a error 12. I however had a mechanic take a look and he said he's only getting 1.6 volts out of the HST controller. He said he really needs the schematics. I'm willing to pay for a download but can't find it on line

It is a 2011 ehydro. I've had an issue in the past and John Deere told me to put dielectric grease on the fitting to the forward reverse sensors. It worked in the past but not this time.

arlen4720 · Apr 29, 2014

You are going to be waaaaaay better off with a John Deere mechanic. He will have the schematic and the tool to plug into the HST controller. However, I do have a schematic for the 4x20. Not sure it would help you (I bet it's close to the 3x20). PM me if you want me to email something to you. It will be too big to post.