Tractor charging

Vinpetrol

Vinpetrol

Well-known member
Just checking - the first shot of the display (with the leads open) has the "1" on the far left of the display, but on the second pic, the .4 is on the right side. When you measured the tow spades, was the "1" on the left or right side?

another thought - do you have a spare light bulb lying around you could put the meter on? (headlight, tail light - anything to test the meter).
The 1 was on the left same as the pic .
Yes I do . Do you mean to just test the resistance ?
 
Vinpetrol

Vinpetrol

Well-known member
IMG_8836.jpeg
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Vinpetrol

Vinpetrol

Well-known member
that's the same reading as open circuit so guessing no continuity -- but as said meter may be suspect???? 1&2&3
alternator heavy brown usually feeds the battery via the main pole on the starter's connection and thence back to the battery - there isn't usually a feed from alternator to battery like that 4
you read the resistance of the length of wire with a probe at each end?? 5
Another meter ordered from Amazon , hopefully get it tomorrow (I have no idea how they do it !)
 
Gecko

Gecko

Well-known member
The 1 was on the left same as the pic .
Yes I do . Do you mean to just test the resistance ?
Yes, just a reality check for your meter - looks fine.

I'm kinda flying blind here as I haven't worked on an A127, but from the outside, all the terminals only have a small number of possible functions/ characteristics.

We've established the Brown/Yellow wire is from the dash light, so a test there is in order.
Disconnect this wire from the W terminal and connect it to ground. Then turn on the ignition and see if the lamp lights.
- if it does, chop the ring off and replace with a spade terminal.
- if it doesn't, it could be a blown globe in the dash.
 
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jd6820

jd6820

Well-known member
As @Gecko suggests we are essentially going round the houses just confusing the job. The wiring diagram you provided and my prior knowledge of Ford Digger/Tractor wiring suggests the Brown/Yellow should lead back to the dash bulb. Grounding this wire should cause the battery light on the dash to illuminate and if left in open air (disconnected) the battery light should go out. It goes without saying this is all with the key in the position (ignition on).

Then we need to establish what purpose the black wire serves. I suspect this is the real issue behind it not charging. You can either bypass the temp sensor if it hasn't already been or simply purchase a different alternator using the same mounting points and use the dash bulb to excite the field and not have any other wiring required.
 
jd6820

jd6820

Well-known member
I wouldn't trust that diagram - if you follow the starter motor high current line, it shows the full start current going through the ignition switch and then a fuse

View attachment 75365
I've found a diagram for a 455 that might be closer (and it shows the A127 as the original Alt)
Not the case I'm afraid, have another look at the diagram. Think you'll find it is running both the coil circuit and supply to the starter relay via two safety switches, this is then connected to White/Red which is the starter solenoid terminal. Not suppling the starter direct.... The diagram is I would say correct for the OP's machine.
 
jd6820

jd6820

Well-known member
sadly you may have cooked your meter trying it with 12v in the circuits - or it might want a battery replacing ..... you should get 0000 on screen with the probes shorted to each other - could also be dirty terminals in your meter's plugs
Nah it'll be just fine as long as he didn't put the any of the probes in the 10Amp position. The internal resistance inside the meter will be in the magnitude of 10Mohms so will pass little current and hence why a multimeter rarely disrupts the circuit it is connected too. More expensive meters have a relative function that allows you to zero out the resistance of the leads (the 0.04ohms) his meter reads when the leads are touching each other.
 
Canal Navvy

Canal Navvy

Well-known member
1, Ground the wire currently fitted to the W terminal. The charge light should light
2, Pull the regulator off and look for brush length and signs of burning.

If both good replace the ring with a 1/4" female spade and put it on the alternator next to the two bigger 3/8" , hopefully you'll then get something like 14 volts.

If not it's probably a better bet to fit a new replacement alternator🙂
 
Vinpetrol

Vinpetrol

Well-known member
Ok . Thanks for perserving with this gents .
Seems I may have a wiring issue as well . I’ve checked the bulb and it works fine . I’ve earthed the brown and yellow wire at the alternator and the bulb is not lighting up. I’ve checked the 12v supply to the bulb (green wire) and it has no power at it with ignition on . There is a fuse with a battery symbol . I checked the fuse location and there is no power to it . I then checked the ignition . I have 12v coming into the ignition via brown wires to 1 terminal when I turn ignition on I have additional power at 1 other terminal which has 3 white wires .
The other 3 terminals don’t change with ignition on or off.
Does is sound knackered ?
IMG_8844.png
 
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Vinpetrol

Vinpetrol

Well-known member
Just looking at the wiring drawing , it is the white wires that take the supply to the fuse box so my issue may be at the fuse box .
 
M

Monkeybusiness

Well-known member
Ok . Thanks for perserving with this gents .
Seems I may have a wiring issue as well . I’ve checked the bulb and it works fine . I’ve earthed the brown and yellow wire at the alternator and the bulb is not lighting up. I’ve checked the 12v supply to the bulb (green wire) and it has no power at it with ignition on . There is a fuse with a battery symbol . I checked the fuse location and there is no power to it . I then checked the ignition . I have 12v coming into the ignition via brown wires to 1 terminal when I turn ignition on I have additional power at 1 other terminal which has 3 white wires .
The other 3 terminals don’t change with ignition on or off.
Does is sound knackered ?
View attachment 75543
Yeah, it’s clearly goosed. I’ll do you a massive favour and give you £500 for it if you deliver it to me in Cheshire….
 
V8Druid

V8Druid

do it as well as you can,but learn to do it better
Ok . Thanks for perserving with this gents .
Seems I may have a wiring issue as well . I’ve checked the bulb and it works fine . I’ve earthed the brown and yellow wire at the alternator and the bulb is not lighting up. I’ve checked the 12v supply to the bulb (green wire) and it has no power at it with ignition on . There is a fuse with a battery symbol . I checked the fuse location and there is no power to it . I then checked the ignition . I have 12v coming into the ignition via brown wires to 1 terminal when I turn ignition on I have additional power at 1 other terminal which has 3 white wires .
The other 3 terminals don’t change with ignition on or off.
Does is sound knackered ?


View attachment 75543
4 or 5 pole switch Vin ???





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Vinpetrol

Vinpetrol

Well-known member
I’ve done a bit more digging , I’ve got the ignition , and fuse box out of the dash and I can’t see any issues at the fuse box .
I’ve also found a wiring diagram that looks much closer to my tractor with 5 terminal ignition
Here’s the drawing and the items list.

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Vinpetrol

Vinpetrol

Well-known member
From the drawing I’ve established that the brown and yellow wire go from alternator to dash light and gives an earth for bulb to light up. The power supply to the other side of this alternator light seems to be my first problem . This supply seems to come from an ignition relay (item 71)
It comes from terminal 87 white wire on the relay goes through fuse 4 and changes to a green wire then goes to the dash bulbs.
I’m assuming this relay may be my problem ?
Can anyone tell me from the drawing how does the ignition light go off once the engine starts ?
Does the brown and yellow from the alternator cease delivering an earth from the alternator or does the 12v supply from the ignition relay stop delivering 12v to the alternator light bulb ?

IMG_8855.jpeg
 
Vinpetrol

Vinpetrol

Well-known member
Once the alternator starts charging what was an earth path becomes a live so the bulb effectively has voltage each side so doesn't light
That’s helpful . That tells me that the green wire on the other side of the charging bulb should be live once ignition is on and also when engine is running.
Now I’m getting somewhere . I need info on the ignition relay now
 
Vinpetrol

Vinpetrol

Well-known member
Is this ignition relay a bog standard relay ?
I can’t find one for sale with terminal 15
IMG_8855.jpeg
 
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