Posted 12/2/2013 10:04 (#3485470) Subject: Need a wiring diagram for a JD4640
Wardview, LA
Please help - I need a wiring diagram (schematic showing the individual wires) for a JD4640 cab tractor. I am having trouble getting the lights to work. I wired two rear lights into the front lights last year to finish planting 125 acres of wheat. The lights worked fine with no issues until this summer they started flickering and turning off when going across the field. You could turn them off for a while and then turn back on and would work for a little while (apparent heat/relay issue). They have no quit working all together. I found one bad circuit breaker which corrected the blower issue I was having, but I can not get the lights to come on. I can run power from the circuit breaker to the lights and they all come on fine. I have confirmed the operation of all four 12V relays are operating and sending voltage out the corresponding wires when the switch is activated. If I knew what wires coming off the three relays under steering wheel went, I can easily troubleshoot and find the problem. I would also like to determine which circuit breaker runs the lights although they all have power going thru them. You help would be greatly appreciated. Feel free to email or text me.
Posted 12/3/2013 19:19 (#3488776 - in reply to #3485470) Subject: RE: Need a wiring diagram for a JD4640
Between Omaha and Des Moines, 7 miles South of I80
This isn't really what you want, BUT I just stumbled on these photos, in JD parts catalog, and thought it may help you , a little.
EDIT: I've got a 4440, and have had problems, with electric connectors, under little right side window(remove that little green curved panel above right-hand battery) There is an electrical plug, right at the bottom of the wiring loom = it get water into it and corrodes the terminals. May what to check that.
Posted 12/10/2013 08:09 (#3506565 - in reply to #3485470) Subject: Re: Need a wiring diagram for a JD4640
Wardview, LA
Thanks for the pics. I had looked those up on John deere parts listing. Here is one I got from our JD dealer. I found the problem where I had someone work on the tractor in the summer - he had wire harness issues and I told him to make it work as I was out of town at the time. I wired the lights up separately, placed them on a new 30 amp CB and illuminated 30 amp toggle switch by the steering wheel. Lights are good to go now and brighter than ever. Only problem is the key switch want start the tractor now. I must of knocked something loose when I replaced the cb and removed the switches for troubleshooting.
Posted 12/10/2013 08:14 (#3506581 - in reply to #3506565) Subject: Re: Need a wiring diagram for a JD4640
Between Omaha and Des Moines, 7 miles South of I80
I had a problem, like that, on my 4440, after I had the plug off the key switch = turns out, I had bent a prong trying to put back on the connector to the key switch = it missed its connection.
You may want to double check, that area.
Edit: thanks for the wiring schematic, too (I saved it, to my computer)
Posted 12/19/2013 08:26 (#3530344 - in reply to #3485470) Subject: Re: Need a wiring diagram for a JD4640
Wardview, LA
Still fighting the ignition switch not working after rewiring all of the lights but should have more time this weekend to review. For some reason, I am getting continuity to ground when I check the wire connection on the starter solenoid. I do not htink it should have continuity to ground unless the safety switch is open (just got figure out where that switch is - it is in series with the ether button).
I have some additional wiring diagrams to post up for everyone and took some pics of the install. I wired a new 30 amp circuit breaker onto the panel, added an illuminated 30 amp rocker switch and ran new 12 gauge wiring throughout except from the circuit breaker to the switch and to the wago block (grey snap in wiring for easy troubleshooting and connections). Hopefully, this will help someone in the future.