Help needed with a re-wire

Please could anyone with some knowledge of tractor wiring give me some help. (posted in the Massey section but the traffic was low).
To cut a long story short, I am having to use a loom for a Massey 135 on a 240 (there is no loom for my year of 240 available worldwide). The 135 loom is much simpler than the 240 and each group of leads has been marked up for me by the supplier but I am running in to some difficulties. There isnt an auto electrician anywhere near here.

First problem I have run into is that the 135 diagram is not very detailed and the book I have, has two for the diesel, one for an early model and one for a late. The loom was adapted by the supplier for an alternator. The early diagram is for a generator the later diagram is for an alternator but I'm not sure which diagram this loom represents. The early one doesn't even have wiring colours.
A further issue may be that the 135 loom is meant for the UK version of the 135 but the diagrams I have from the IT book were meant for the US version of the 135.

The second issue I have come across so far is the ignition switch terminals: the 240 has more than the 135 and seems to be numbered differently.

Are you with me so far??

I'm going to try to deal with each part one by one. The first is the ignition.
The 240 diagram is marked as follows:
Pole:
1.2x brown. One to starter and the other to lights/horn switch.
the 240 loom has no lights except 2x warning lights (alt and oil)
2. Light green. To fuse box. Supplier said the fuse box wont be used and has put an inline fuse on a thick red cable amongst the ignition bundle.
3. Black. To thermostart
4. Yellow. To starter

The cables for the ignition have been marked as follows:
Red: Ignition
1xBrown: Battery
Blue/white: start
Brown/Green: Glow plug.

I have done my best to work it out and put them as follows but I may well be wrong:
Pole:
1 Brown
2. Red
3. Brown/green
4. Blue white

Is this right?

If I were you I would forget about the diagrams and just plan out what has to be hooked to what. If it has an
alternator it is simpler than a generator. You have to figure out what powers what, and use a voltmeter and continuity
tester to determine the appropriate switch terminals to use, etc. Of course this will be possible only after you
understand the basic workings of the starting circuit, charging circuit, ignition circuit, and lighting circuit. It
helps to break it down and tackle one circuit at a time--tends to take some of the mystery out of it all. Good luck.

the 240 loom has no lights except 2x warning lights (alt and oil)

Click to expand...

should have written: the 135 loom

Have no idea what a continuity tester is let alone how to use one.
I think this must be beyond my capability.
Not sure what to do now.

It sounds as if you are shooting into a dark hole. You need that coniuity tester and be able to understand what you are up against.

Jim at Agri-Services list a wiring harness for a 240

(quoted from post at 06:13:11 09/25/16) Have no idea what a continuity tester is let alone how to use one.
I think this must be beyond my capability.
Not sure what to do now.

Click to expand...

A continuity tester is similar to a penlight flashlight, in that it has a battery(s), a lead wire with clip and a metal point. When the clip from the lead wire is touched to the metal point the light will light, indicating continuity. To use with your harness, you will clip the lead wire to a wire at one end of the harness and then probe the wires at the other end. When the light, lights you have identified the other end of the wire - it has continuity. For example: if you want a brown/green wire to go from the switch to the thermostart, clip on to the switch end of the wire and probe all the wires at the other end of the harness. You are looking for the light to light for the thermostart connection(s) and no other wires should show continuity. In this manner you simply work from the 240 wiring diagram making one connection at a time.

There is a similar tester called a "test light". It has a lead wire/clip, metal point and contains a bulb - it has no battery. To use, the lead wire is typically connected to a ground source and the light will light when the point is touched to a source of 12 volts.

Both testers are available at NAPA or other parts stores and can be had for $10 +/- each.

It would be helpful if you post the 240 wiring diagram you are working with.

You need to teach yourself that. It can be a meter or a light that tells you if a wire is sound from point A to point B. By touching each end with the meter or light leads you can tell if the wire is good.

whats your location RedMF
there maybe someone within reason that might be able come over n help you in person
if your close enough to me I would be glad to help
as a tractor is pretty basic of a wiring setup I usally just make up my own wiring harness
they won't match the colour charts but they work well and are trouble free
as you say you have no running lights
you need a wire from your alt for charging
one keyed through a light to excite your alt and one for your coil
if it's got an oil light keyed wire to light and then from light to the oil pressure switch
one from the key to main post on your starter or to the positive post on the battery to give voltage
at the key
one from your key switch back to the small stud on the starter to activate the solenoid

Red, I like the way Ray Tractor approaches it, one system at a time!

Don't let this overwhelm you! You won't believe this, but the hardest part of installing a wiring harness, is installing it! Getting the thing strung through all the places it needs to go so it doesn't get cut, burned or pinched, and all the wires reach where they are supposed to go! If you have done that part, the rest is easy!

Remember, any adapted, fit all, even factory harnesses have extra wires that will not be used in your application. Look at any car or truck, you will see dead end wires hanging everywhere!

Start with the obvious. One circuit at a time. I like to make temporary connection first, don't cut anything until you are sure. Once you get it to the point you can make your battery connection, start with everything turned off. Temporally sit the battery cables on. There should be no spark. Remove the battery cable. Then, for example, turn on the light switch. Sit the cable back on. It should make a small spark and the lights come on. If it pops, remove it immediately, something is wrong. If the lights come on, that circuit is right, move on to the next one.

Once you get everything working, go back and tidy everything up. You want this to be a neat, profesional looking job when you are done. Use lots of small black zip ties, shrink tube and solder whenever you make a connection. The split black harness tubing makes for a clean look, and helps protect the wire from thee elements. Avoid tape! It will look good for a short time, then it will start coming unraveled!

Remember to use what you have been provided. A good wiring harness will not repeat colors. You can be reasonably confident that a particular color wire is the same circuit wherever you see that color in the harness. Some harnesses are not color coded, they will be numbered. Same applies, that number wire will be interconnected throughout the harness. Also you can search for wiring examples. Look under "Images". It doesn't have to apply to your specific tractor. Example, "Delco Alternator Wiring" will show dozens of examples, look them over until you find one that you can understand and apply.

Get yourself at least a test light, preferably a test light and a cheap multi meter. They are simple instruments, a real easy way to tell if a circuit is live when it's supposed to be, or a connection is made with what you think it should be. The more you use them, the more comfortable you will get until you wonder how you ever did without them!

Do what you can, then if you get stuck, ask again, be specific. We'll talk you through it!

Thanks everyone for your advice and suggestions; much appreciated.
I can see that it might be possible for me to get it almost right but there is a high chance I wouldn't get it completely right and that could mean a fire which isn't worth the risk. The 240 was notorious for fires unless it had a proper re-wire. The original loom and the way the whole system was designed, was a total dogs breakfast. My supplier told me that over the years whenever a customer would ring up and tell him his tractor had caught fire, it was nearly always a 240!
I did get the only 240 loom on the market (imported from Ireland) but it was nothing like the wiring on my tractor: I think it is for the modern Pakistan version of the 240, not for a UK built '79. The only sparks in town took one look at it and refused to do the job and made it clear he wasnt interested in working with the 135 loom either.

The parts supplier had said from the start that there wasnt a 240 loom for mine and to use an adapted 135 loom which was much simpler and had none of the mess of the 240 wiring design. They have done it this way for years but it would cost me hundreds just in travel costs to get their sparks here.

I am thinking of asking a local mechanic if he could come over and do the job because if some of you guys think an amateur [b:090a101ce2]might[/b:090a101ce2] be able to do the job, then I would have thought a mechanic with a lot more experience with auto electrics would be better than an amateur...he doesnt need to be an auto electrician.

Anway there is no option now of taking the tractor anywhere as I finally took the plunge the other day and stripped out all the old wiring and cleaned all the dirt out of the inside of the dash and where the loom runs through. Looking at some of the wires, I'm amazed there wasnt a fire before. Actually I'm not, there was once some smoke from behind the dash!

Thanks again, everyone.

Don't beat yourself up too much. I had wiring issues with my 1997 MF-240-S, impossible to resolve, Come to discover two extra fuses in clever little black twist-together fuse holders hidden under the dash, not shown in my owner's manual or any other manual. Mysteries, but when I replaced them everything worked. The little black flasher unit itself is not to be found in the known universe, I think I found the last one in Turkey or someplace, and I have it up on a shelf with a spot-light on it. Lord knows what I'll do if I ever actually use it.

Been through a similar thing.
Mine has a hazard warning switch from Hella Germany but the knob was partly missing. Spent many hours staring at pictures of hazard warning knobs on google images :shock: , trying to find the discontinued knob from Hella. Eventually matched it with almost the same knob from a 70's VW Beetle.

The real mystery is these British engineers who designed the MF's also designed the Supermarine Spitfires and the Hurricanes that devastated the Luftwaffe.

By 1979 they had lived through Wilson, Heath and the dawn of Thatcher. They needed Leyland Supercover for all the cars built on a friday afternoon / monday morning.
I look at how well built my tractor actually is (notwithstanding the wiring design) and am amazed that they were still capable of producing such well machined parts by '79.