M4500 DT wiring diagram ?????

[westcliffe01]

Folks, I had a 60A inline fuse disintegrate in my M4500 wiring and the firewall mounted fuse block is corroded and flaky. I basically lost all electrical function on my machine and eventually traced it to the disintegrated inline fuse in the B+ line that goes from the engine to the starter.

Buttt.... That is still not the end of the electrical issues. The electrics on this machine have never worked 100% since I got it and the alternator has never worked at all. The previous owner removed all the sheet metal when he did a restoration on it and I think he meant well since he replaced a lot of parts that needed replacing. But clearly electrical work was not his forte.

It seems the alternator on this tractor has no internal regulator and uses the firewall mounted regulator similar to what a lot of generators used. Today I removed both the alternator and the regulator and cleaned the contacts in the regulator. I was hoping I could find identifying marks on the alternator itself but no luck with that. There is an aluminum sticker on the frame that is oval, but any inscriptions on it are long gone. It has the usual B+ positive nut connection and then a 3 spade electrical connector labeled N F and E. From my google research on 70's and 80's toyotas, it appears that this is a common pinout and all 3 of these connections go to the external voltage regulator. I have an operator manual for my machine in PDF format and it has a wiring diagram, but it is a scan of a document which I think was photocopied about a dozen times before it was scanned so the quality is not the best. I cant tell wire colors and in places the wires disappear and re-appear.

Is there anyone here who perhaps has a good quality wiring diagram for this series tractor ? Is there anywhere one can access a good quality diagram ? I looked under Messicks parts section but they do not have wiring diagrams....

This is the best info I have, but the location of the charge light is not shown in the circuit.

 

[Dave M7040]

Sent you a private message

Dave M7040

 

[Gearloose]

If you need more info, Kubotabooks.com recently added 2 wiring diagrams for the M4500 - one is a general schematic, the other a detailed diagram. The detailed one has some wiring colors that don't match mine, but in all other respects it is excellent and includes items that aren't found in some other M4500 diagrams, like reverse light circuit, stop lights etc.

 

[westcliffe01]

GearLoose, your reference has been a real help. Along with the not very legible Kubota wiring diagram, there is a second diagram that someone appears to have recently drawn out that is very clear and I will be using that to make a new wiring harness for my instrument panel.

I patched it together well enough that it works, but its not very intuitive for anyone but myself. Some of the contacts on the ignition switch were bad so I routed power to the start / glow switch without going to the start switch and the only reason one needs to turn on the ignition switch at all is to make the alternator come alive and provide power to the instruments. If you run the tractor and leave the switch on, it drains the battery and if you leave it off the alternator wont charge and the battery runs down. Mainly a problem if someone else neds to use the tractor and Im not around...

 

[Gearloose]

Glad to hear that it helped. The 2 page wiring diagram is what I donated to Kubotabooks. Can you send me the link to the hand-drawn one? I didn't see it.
I found the detailed diagram fairly easy to read once it was zoomed in or printed A3 size. I tried scanning the original in different resolutions but going higher res than what I think you downloaded made little difference to legibility.

If you need the full workshop manual PM me.

 

[westcliffe01]

Page 2 of the file at the link http://kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=M4500%20electrical%20wiring%20diagram%202%20pages%20ex%20WSM.pdf

Glad to hear that it helped. The 2 page wiring diagram is what I donated to Kubotabooks. Can you send me the link to the hand-drawn one? I didn't see it.
I found the detailed diagram fairly easy to read once it was zoomed in or printed A3 size. I tried scanning the original in different resolutions but going higher res than what I think you downloaded made little difference to legibility.

If you need the full workshop manual PM me.

 

[Gearloose]

Thanks westcliffe01, all clear to me now.

 

[orop]

If you need more info, Kubotabooks.com recently added 2 wiring diagrams for the M4500 - one is a general schematic, the other a detailed diagram. The detailed one has some wiring colors that don't match mine, but in all other respects it is excellent and includes items that aren't found in some other M4500 diagrams, like reverse light circuit, stop lights etc.

Looked in vain for those wiring diagrams you mentioned. Any chance you can send them to me via email? All I can find are three (as far as I can tell) identical parts books for the M4500DT.