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Alternator Not Working

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The bushes looked fine when I last looked, but I'll check lengths etc.

Thanks mikey, I'll try that

Can anyone confirm where the three wires (and how i can identify them) should go please?

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Three wires :s

Yeah, I was confused by that too. Should really only be 2. Maybe there's the feed from the battery to the alt, then back off to the starter. Only because he said they were all equal thickness? :s

You're not testing the bulb here. Putting 12v onto the blue takes the bulb out the circuit, and with the engine running, you should be able to get voltage increase over the battery.

If this works, the alt is good, and the blue feed is broken/bulb is gone.

Three wires :s

3wires is correct. there are 2 versions of the setup. a 3wire plug or a 2 wire ring loop

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Aye, one red goes to the starter.

If the bulb isn't the issue, what else may be the cause?

It can only be a break in the wire to the bulb, and from the bulb to the *ign live?

*Not sure if that's where it goes. Certainly to a live feed on ign though!

I'm confused with 3 connections.

Surely there should be the one to Batt and the blue wire and that's it?

Or is it a wire from batt, then another wire to starter?

Aye, one red goes to the starter.

Or is it a wire from batt, then another wire to starter?

Why two connections though lol, both on one would be fine

Maybe it's to save wire? Although, you'd think then from batt to starter solenoid then to alt.

Think it's just to piggyback to the next component. Haven't seen it though, so just guessing..

Dunno 6n has one lead just with a flat part with a hole, like a lot of cars.

Wouldn't have thought that they'd unnecessarily use an extra connector, another component on the car (extra wire) and an extra terminal on alternator etc.

Must be a reason lol

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I'll take some photos for your harris

His name is Nick! haha

But we all know him as Harris, if you say Nick then nobody knows who you mean..

  • Author

Thanks for all these ideas, really helpful. Are there any more potential causes? I'm trying to build up a list of things to check as I'm heading over to the car at the weekend, so want to have more than one thing to check, in case the first thing I try doesn't sort it. If that makes sense :?

Yeah. You can measure continuity on the rotor between the brush contacts.

Continuity in the field windings.

Brush length.

Check it has a good ground & power/12v+ connection.

Take wire to make the blue wire connection direct to batt.

  • Author

Cheers. There shouldn't be 12V GOING to the alt should there, but i'm guessing I can check at one of the terminals of the alt if its pumping out current aye?

It's connected to batt & ground, will be batt voltage.

You need 12v at the blue wire to excite the field windings as previously stated.

  • Author

Yeah, I'll check that. So the 12v of the blue need to be at the 12v end, not the alternator end. Word.

I'm hoping its a blue wire issue here. If its all gone to shit, can I connect the blue wire to an ignition live to get the smae effect?

The bulb will probably be gone.

The alt has 12v batt permanently, once the engine is started it gets 12v to the blue wire, that's all.

If you don't have a rise in batt voltage, the alt is goosed.

  • Author

Right then, I'll wire the blue directly to batt and then see if I can get more than 12v across the batt with the car running

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Continuity between all components is fine. With a live going directly to the blue wire, there is no change in voltage across the battery with engine on.

The bulb still doesn't light, regardless though. Whether the alternator is shagged or not, this should come on right? Fuck this

Has anyone mentioned the regulator on the alternator? maybe its shot n all open circuit. If it is then u will get 0 volts coming out the alternator. Just a thought. Had one do this on me before. I got another regulator at GSF and it solved my problem. If somebody already mentioned this then sorry. Ignore this post lol

Continuity between all components is fine. With a live going directly to the blue wire, there is no change in voltage across the battery with engine on.

The bulb still doesn't light, regardless though. Whether the alternator is shagged or not, this should come on right? Fuck this

  • Author

Its not been mentioned, so thaks. Is the reg on the alterntor itself? I assume from your post its a serviceable part

It is, yes, Atleast on the older ones.

But open circuit would leave you with 0v. And with the bulb's other side high 12's, it means it'll light.

And there's no other way to get 12v's to the reg.

So I doubt it's that.

Most likely bad clocks/earth/wiring. You've got other senders not working, so it's something simple man.

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