D-250 Wiring Harness part # mystery

[Ironman 115]

Ok, so recently I picked up a 1978 D-250 (81-20RG01) and mechanically it looks really solid. Cosmetically it's a mess but that's no big deal. The problem is the wiring looks like a rats nest! Things spliced all over, and nothing electrical works properly. (Most not at all) When I bought it I thought, No big deal, I'll pick up a wiring harness and see where I stand from there. Here's the problem...I can't find a part number for the wiring harness anywhere! When I do a parts lookup all I see is individual wires listed. Please don't tell me that out of all the wiring harness' I see for sale everywhere (only listed by part #'s) that one doesn't exist for the 250? Am I missing something here? Any help would be greatly appreciated.  

[stratostar250 919]

Sorry to tell you, but almost all parts for the D-250 have been discontinued.  And they are also very tough to find almost anything in general, used or NOS, and sorry to bring worse news, but I am positive that you cannot buy a new wiring harness.  If you are lucky, you may be able to find a used one on ebay, but that is probably about it.  I uploaded the owners manual for the D-250 a few months ago,  Ill put a link for you;  on the third to last page, there is a wiring diagram, which I hope can help you! It is the download that is 4.89 MB not the smaller one.  

Edited January 15, 2015 by stratostar250

[gwest_ca-(File Mod) 11,040]

The diagram in the service manual has more detail than the one in the operator manual.

 

Wire insulation colors and metric wire gauges included

 

Garry

[Ironman 115]

Thanks Garry & Tom, I kind of figured that most parts would be impossible to find, but I thought that someone may have repopped a wiring harness. I see tons of brand new harness' on ebay but they all go by parts number. That's the weird thing here...The wiring harness for the 250 doesn't seem to have one that I can find. I have found a great source of engine parts. Jacque's rear engine Renault parts. http://renaultparts.us/

[stratostar250 919]

Thanks Garry & Tom, I kind of figured that most parts would be impossible to find, but I thought that someone may have repopped a wiring harness. I see tons of brand new harness' on ebay but they all go by parts number. That's the weird thing here...The wiring harness for the 250 doesn't seem to have one that I can find. I have found a great source of engine parts. Jacque's rear engine Renault parts. http://renaultparts.us/

No problem, Rich! And I agree, It would be really nice if someone made one, because my electrical is a little iffy here and there too.  Sometimes I have to wiggle a fuse or a wire for everything to work correctly.    But I have heard good things about that website and it's owner.  Good to know that if need be, there's a source!  

Edited January 15, 2015 by stratostar250

[Shuboxlover 478]

I have a good harness for an early D-250...... but that won't do you much good.....your best bet for sure would be to fix the one you have by following the schematic.  The Germans might be able to design a good U-Boat, but the jury's still out on garden tractors......

[Ironman 115]

LOL, I hear ya! Why does it have to be electrical? I could do just about anything else in my sleep, but hate electrical! I think for some reason I just have a fear of it or something so I never had any interest in learning about it. I'll do my best, Thanks.

[blu_stang 14]

Another hobby of mine is building electronics and electronic systems of all sorts. I've cobbled together all sorts of wire, cables and connectors for those activities.  From that experience, I don't think the wiring harness on the D250 would be all that difficult to build yourself.  I'm lucky, in that most of the wiring on my D250 is in relatively good shape. But I do have a couple of shorts that seem to cause the occasional lighting flicker. I've already begun to look at the possibility of replacing at least some of my wires on that tractor.

 

The wires in my '76 D250 all seem to be 16 or 14 AWG "color coded" wires for the 8 amp circuits, or the '70's metric equivalent of these US sizes. The terminals are all crimp-type spade or push-on (the flat guys) connectors.  These all can be found at the likes of your favorite auto parts, hardware (HD & Lowes for sure) and RadioShack or Best Buy.  With this, you can simply replace one wire at a time, with the existing wires and the diagram as a reference.  Unlike the autos of today, these tractors don't have a true cable harness with Molex connectors, but rather a collection of wires zip-tied together.  

 

 

I've learned a couple of tricks for automotive type wiring:

 

I like the crimp terminals with heat shrink wrap for a permanent connection.  They do well to protect the copper wire coming into the connector.  I don't recommend using a flame to shrink, heat shrink.  It will often melt the wire jacket.  A hair dryer or heat gun are best.

 

Crimp twice and tug.  Make sure the connector doesn't slip off with a solid tug.  

 

"Bundle" wires where you can, once they are all flowing in the same direction.  Zip-tie down any individual wires through their path, every 12-18". Rattling wires can be incredibly annoying. The same stores I mentioned sell sheathing that you can either wrap around a set of finished wires, or feed them through and zip-tie or tape the ends.  This does a few things:  

                - makes for a nice clean compartment, with wiring

                - provides added protection from the elements

                - keeps one wire from getting loose and finding it's way into moving parts

 

While you're replacing wires you may also want to consider replacing the original fuse block with a new one.  Generic ones are available at the auto parts store for less than $10.  That will give you the opportunity to switch to the type of automotive fuses we use here in the US, which are much easier to come by.

 

If you feel comfortable with a wire cutter and a crimper, you should have little trouble replacing the wires.

 

Good Luck!

 

~Greg

Edited January 17, 2015 by blu_stang

[Save Old Iron 1,566]

mm to awg wire conversion

 

http://www.rapidtables.com/calc/wire/swg-to-mm.htm

[Ironman 115]

Thank you Greg!!! You make it sound so easy. lol...I understand what you're saying though. If I look at it as one wire at a time it's a very simple job. I have no trouble with connectors and heat shrink tubing, and I'm very organized and neat about my work so it really shouldn't be a problem. I'll take your advice on replacing the fuse block also. I'll keep it clean and simple. If I run into any trouble I'm sure you guys will help me out. Much appreciated!!! 

 

Oh And Thank you Save Old Iron for the handy Metric conversion chart! Very useful.

[blu_stang 14]

Rich, et. al, 

 

I have some more details about the replacement wiring, I want to share.  I looked up what the D250 repair manual specifies. Chapter 7, figure 7-7 has wire sizes in a couple of the diagrams, all specified in metric units. If you do the conversion for just the signal and light wires (8 amp circuits) you come to 14 AWG wire. Now, there IS a catch to this...

 

These specifications were made at a time when all wiring like this was pure copper.  Since then, many industries have begun the switch to Copper Clad Aluminum (CCA) for their standard wire use.  This is important because CCA doesn't conduct electricity quite as well, but it's much less expensive and is lighter.  Low cost wire and many trailer lighting kits, with different wire colors, will most likely be CCA (look for it on the label).  Sanctioning bodies such as the National Electrical Code (NEC) and the Consumer Electronics Association (CEA) have caught on to this and are using a rule of thumb for replacing old copper wire with CCA.  They recommend you use wire that is two gauges thicker for wire made of CCA than if it was made of pure copper.  

 

So, for example, in the 1.5mm, 8 A circuits, if you have pure copper wire to use as replacement wire, use 14 AWG.  If you have CCA wire, use 12 AWG.  This will ensure you have properly sized wire for the current through the circuit.  I’ve made the rest of the size conversions, below:

 

Metric                AWG – Copper            AWG – CCA

1.5mm              14 AWG                       12 AWG

2.5mm              10 AWG                       8 AWG

4mm                 6 AWG                         4 AWG

 

There’s also what looks like a grounding wire for the battery and starter specified for 16mm, in the same diagram.  I can’t tell if that is a typo, a bad scan of if the 16mm spec is for a flat braided ground strap.  But I can tell you that I've worked on several car electrical systems rated for 100 – 200 A and the largest gauge wire I have seen used with some frequency is 00 AWG.  00 or 0/2 AWG wire is about 9.26 mm around and it is massive!  Most auto applications stop using a crimp connector at 4 AWG, and switch to a terminal that uses a set screw to secure the larger gauge wire.  Needless to say, I don’t trust that number as I have read it.  Most automotive ground wires from the battery, starter, or alternator to the chassis are 4, or occasionally 2 AWG.  Which is plenty big around for a 150 A system in a car for the very short (less than 18â€) run to the chassis.  A 0/1 (8.25mm) AWG wire or a 0/2 (9.26mm) AWG wire might be needed if you were relocating a battery, running a big sound system or other very high current (100+ A) accessory to the other end of the vehicle. 

 

Hopefully these more definitive answers will be a bit more helpful.  It’s a lot easier ordering supplies when you know exactly what size you need.

 

~Greg

[Ironman 115]

Thanks Greg! If pure copper wire is still available (which I assume it is) I'll stick with that. I've read that when mixing the copper and aluminum (in a house at least) that there is problems with excessive corrosion or oxidation of the aluminum wire. In any case, I would rather use slightly heavier gauge than to scrimp on cheap inferior wire and connectors. It appears that's what the owner before has done as nothing is color coded the way it should be and the connectors are all the cheap Walmart style. All of the spade connections are loose and corroded with the blue plastic insulators are crushed and mangled. I'm determined to do it right and will do my homework to make sure that it is.                                                                                                                Thanks so much, Rich