Nuffield Universal 3 Wiring Overhaul

Kadidlehopper · Jan 3, 2016

Could someone more experienced then I look at this wiring diagram and tell me if they can spot any problems with it? Im fairly new when it comes to wiring and dont feel like lighting the ol girl up one day cause of inexperience.

Blue dashes are line fuses

the red wire is one im not too sure about as it was connected to the old & removed control box before the gearbox ground

Im hoping to install a voltmeter instead of an ammeter

alternators a delco remy 1 wire alternator

tractors a Nuffield Universal 3

Ive also been advised to install a kill switch near the battery terminal, but considering the whole thing is turned on via an ignition key switch, would I need to?

thanks

Wiring diagram Nuffield 4DM solenoid starter-page-001.jpg

davesl708 · Jan 3, 2016

HI. Welcome.

The schematic looks fine. The red wire (marked as black on the drawing) highlighted is a ground wire and should be grounded.
Changing to a volt meter should not be a problem.
Installing a kill switch at the battery will stop any parasitic drain on the battery from a loose ground wire or a partial short in hot wires.

banjodunn · Jan 4, 2016

G'day sorry but the wiring is not right the brown wire you have going from the voltmeter to the starter should not be there as it needs to supply power only in the start position also voltmeter will only work when cranking, do you have an off/on/start ignition key? If you do then you will need to find the terminal that is live in the start position only and run it to the small terminal on the starter solenoid. As for the fuses on the lights put them back as close to the light switch as possible then you protect all the wiring to the lights, run your panel light off the light switch that runs your headlights as this should be powered up when in worklight position too. Other than that it looks good.

PS Put a fuse on the charge wire down at the battery in case you ever have an alt or wiring short this will need to have a fuse as heavy as what the alternator maximum output is.

Jon

skyhook · Jan 4, 2016

banjodunn, is correct, it looks like you have a "push-button" starter switch, (you push this button to start) if this is correct, the brown/white wire from it should be removed and replaced with the "brown" wire from the volt meter,(it comes from your starter solenoid) If you remove that "Red" wire, your horn may not work, it's a ground for the horn, but the horn "may" be already grounded through it's body.

Dave M7040 · Jan 4, 2016

As a Nuffield owner I found this UK form to be filled with very knowledgeable, helpful people.
Suggest you join and you will have access to a lot of specific knowledge and documents.
The fact that, as you have stated, your wiring diagram shows a one wire Chev or GM alternator tells me that a lot has been modified.
The tractor could have been a positive ground one before the alterations started which will greatly complicate things as far as the instruments and dash wiring is concerned.
The fact that I don't see any mention of a neutral safety switch in the circuit to the starter solenoid is a great concern. Many people have been run over starting their tractor while standing beside them or if they jump out of the way the tractor goes through the back wall of the garage. The switch is likely on the top of the transmission case near the driver's seat. The wiring to the starter solenoid should go through this switch first.
Typically there would have been a voltage stabilizer device behind the dash to make the instruments work properly. It would be a narrow metallic container about the size of a finger.
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Dave m7040