Mystery wire

Can somebody tell me where this blue wire goes on a 3020 there are 3 blue ones but I can only find 2 in this part of the harness

Maybe the oil pressure switch?

3020 diesel converted to 12 volt

The oil psi switch is hooked up

The manual should have a wiring diagram with color codes.

I?m looking at it trying to find where it goes

Blue 01 used to go from the top of the 24 volt starter solenoid thru one of the starter circuit breakers to Bat A terminal on the ignition switch with a splice to terminal B on the 24 volt voltage regulator. Blue 06 was a straight shot single wire for the oil pressure light circuit.

What appears to be purple or very dark blue from being inside the harness for most of it's life might be the stub of Blue 01 from the starter circuit breaker to the now defunct 24 volt starter solenoid? I would verify that Blue 01 is also disconnected from the ignition switch and then forget about it as it seems to be unused in the 12 volt situation. There was a connection from Blue 01 to the rear power outlet though and that might need rewiring to 12 volt positive these days. No purple in the diagram I'm looking at and no other color that could be even close to blue either.

I think Lee is correct. If your tractors wiring harness was a replacement with circuit breaker kit IIRC it wasn't shown in TM or PC.

Since it was converted (what you said) over to a 12 volt system (like so many were) I cant be sure not being there, but I think YOU DO NOT NEED that wire PROVIDED the oil pressure and any 12 volt receptacle if required works. That picture of what I call a "Ford Type" solenoid ONLY uses the two big IN (from battery) and OUT (to certain 12 volt loads) stud posts, while the small S terminal is the 12 volt activation which closes the solenoid when power is applied.

HAPPY AND BLESSED THANKSGIVING TO ALL

John T Retired Electrical Engineer

(quoted from post at 22:00:30 11/22/17) Can somebody tell me where this blue wire goes on a 3020 there are 3 blue ones but I can only find 2 in this part of the harness

Click to expand...

As to the paired matching colored light blue wires, they were originally connected to the starter solenoid post with the (-) battery cable. One went to the BATT terminal on the old igntion switch, the other supplies power to the key switch and light switch.

The darker blue wire connects to the oil pressure sender.

If something is connected to it now other than the blue wire, it's been "farmerized".

Thanks for the vote of confidence Tx Jim. Only now I can truly appreciate the controversy over this system as the site that is still hosting this PDF file below also has some jpegs of other JD 24 volt systems with hard ground cables at both batteries. Even the PDF below leaves out the small fused ground connection at the rear left battery post while it does indicate it with 'to ground' label. The Brown 02 wire at the voltage regulator is not correct in showing a GND connection there - it may well be labeled as GND on the regulator connection tab, but I've checked with meter and it certainly is NOT ground, it is hot 12 volt positive at all times in relation to engine/frame ground. The connection tab may have been embossed GND in mass production where changing it to a more appropriate label was just too inconvenient or costly to correct. An experienced mechanic would disregard the GND label without too much thought or concern as other instances of same issue is part of the learning curve of being a professional mechanic, but the hard headed farmer without such history may swear on the bible that this is supposed to be GROUND - and it just isn't so. I can see a whole lot of debate fuel right there, please be careful with the matches. Google the PDF name below for that site.

Apparently this is the closest we can ever come.
<a href="http://charliemckinley.com/3010/Gary_Wece_Wire_Diagram_colored.pdf" target="_blank">Gary_Wece_Wire_Diagram_colored.pdf</a>

This file used to be hosted by Gary Wece's Geocities site which is no more and that means if you don't save this one soon, it too will disappear from the web before you know it.

"As to the paired matching colored light blue wires, they were originally connected to the starter solenoid post with the (-) battery cable. One went to the BATT terminal on the old ignition switch, the other supplies power to the key switch and light switch."

CORRECTION...

I meant to write "One went to the BATT terminal on the old VOLTAGE REGULATOR, the other supplies power to the key switch and light switch."

Thanks for all the replies . The tractor starts and charges fine so I guess I won?t worry about this wire for now I?m planning on putting an oil psi gauge on it eventually I?d like to replace the wiring harness as it?s getting a little brittle after 50 years