12ht alternator connection (1 Viewer)

[rideglobally]

There are two post on the alternator the white is positive. The other is negative correct? Can i connect the black negative wire anywhere I can get ground (negative) or directly to battery negative. Are these the only two wire connected to these two post? Is there another wire? As you can see I have the original harness that connects to the green plug on top of the alternator. See picture thank you.

 

[duncanrm]

A few things..

• Your factory harness has probably been hacked a few times.. I'm not aware of any 12HT models that came internally regulated from factory (entirely possible I'm wrong)
• White is your alternator output.. usually shown as "B+" on most diagrams, it'll wire to your battery+ via a fusible link
• The second stud showing on your alternator where you have a black cable connected is just a mount point for a bracket - there's usually nothing hooked up to this, the alternator is earthed through its body and mounting to the engine.
• If you've just put this alternator in as a replacement - double check there's definitely no external regulator and the vehicle has been correctly converted to internal regulation

 

[rideglobally]

A few things..

• Your factory harness has probably been hacked a few times.. I'm not aware of any 12HT models that came internally regulated from factory (entirely possible I'm wrong)
• White is your alternator output.. usually shown as "B+" on most diagrams, it'll wire to your battery+ via a fusible link
• The second stud showing on your alternator where you have a black cable connected is just a mount point for a bracket - there's usually nothing hooked up to this, the alternator is earthed through its body and mounting to the engine.
• If you've just put this alternator in as a replacement - double check there's definitely no external regulator and the vehicle has been correctly converted to internal regulation

My old alternator was hacked because my internal regulator went out. An external regulator was installed. This is a new alternator. I am trying to wire it to my existing/original wire harness. That white wire and the green connector are the original wire harness. I don’t remember what is connected to the other stud where the black wire is connected. Do I have the white wire connected to the correct stud? I believe that is my B+ wire.

 

[duncanrm]

My old alternator was hacked because my internal regulator went out. An external regulator was installed. This is a new alternator. I am trying to wire it to my existing/original wire harness. That white wire and the green connector are the original wire harness. I don’t remember what is connected to the other stud where the black wire is connected. Do I have the white wire connected to the correct stud? I believe that is my B+ wire.

Yes white wire is correctly connected.

 

[rideglobally]

Yes white wire is correctly connected.

do you think my fuseable link is not good? Can I run a wire where the white wire is connected directly to the positive battery with a 30amp fuse? I am on the road. I will disconnect the black wire, that stud is holding down the bracket for the green plug in.

How can I locate the fuseable link on my white wire?

 

[duncanrm]

do you think my fuseable link is not good?

You have a fault?

You should test continuity between your B+ Alternator Stud and the positive terminal on your battery.

Fusible links will be somewhere just downstream of the positive terminal of your battery.. but after so many years its anyones guess whats going on with the wiring on any specific vehicle. Google "landcruiser fusible link" to get an idea what you're looking for.

 

[rideglobally]

You have a fault?

You should test continuity between your B+ Alternator Stud and the positive terminal on your battery.

Fusible links will be somewhere just downstream of the positive terminal of your battery.. but after so many years its anyones guess whats going on with the wiring on any specific vehicle. Google "landcruiser fusible link" to get an idea what you're looking for.

Ok I will check continuity. If there is a fault can I connect a wire with a 30amp fuse directly to the positive terminal of the battery? I am on travel I will not have access to a fuseable link.

 

[rideglobally]

I am currently in La Spenzia, Italy.

 

[duncanrm]

Ok I will check continuity. If there is a fault can I connect a wire with a 30amp fuse directly to the positive terminal of the battery? I am on travel I will not have access to a fuseable link.

30A may not be sufficient, especially if you were to turn on spotlights etc.. I suspect your fault is not in your white wire though. A proper diagnosis of your alternator wiring needs to occur.

 

[rideglobally]

30A may not be sufficient, especially if you were to turn on spotlights etc.. I suspect your fault is not in your white wire though. A proper diagnosis of your alternator wiring needs to occur.

Ok I will check the white wire continuity, in a few.

30A may not be sufficient, especially if you were to turn on spotlights etc.. I suspect your fault is not in your white wire though. A proper diagnosis of your alternator wiring needs to occur.

you are correct there is continuity on the white wire to the positive battery terminal.

 

[rideglobally]

How do I diagnose the other wire connections?

 

[rideglobally]

I disconnected the black wire.

 

[duncanrm]

Green plug needs to be checked for correct conditions to excite alternator.. diagram orientation is looking into the plug on the alternator.. as per description. Best done with an incandescent test lamp, not a digital meter.

 

[rideglobally]

Green plug needs to be checked for correct conditions to excite alternator.. diagram orientation is looking into the plug on the alternator.. as per description. Best done with an incandescent test lamp, not a digital meter.

View attachment 3429977

I have a test lamp and a multimeter. Is this done with the engine running? How is the test done? Where do I connect the positive and negative on the test lamp? I am away from my rig now I will do the text later. Thank you for your help.
Question: since there is continuity on the white wire to positive battery terminal does this mean my battery is getting charged even my gauge says no?

 

[sodafeld1]

Duncan is doing a good job.
Just to make it clear to me, you have an external regulator already installed? And you are using this already existing harness with the external reg to the new alternator?

That alternator looks like it has an internal reg.

Don't think things are happy with 2 regulators.

If you have a cig lighter volt meter plug it says what your battery is charging at whilst running , or the multimeter running across your battery whilst running.

The standard alternator gives 80amp and some newer give 120amp and some even more, you want more than a 30amp fuse.

 

[rideglobally]

Duncan is doing a good job.
Just to make it clear to me, you have an external regulator already installed? And you are using this already existing harness with the external reg to the new alternator?

That alternator looks like it has an internal reg.

Don't think things are happy with 2 regulators.

If you have a cig lighter volt meter plug it says what your battery is charging at whilst running , or the multimeter running across your battery whilst running.

The standard alternator gives 80amp and some newer give 120amp and some even more, you want more than a 30amp fuse.

This is an internal regulator alternator. My original regulator was also an internal regulator, the regulator went bad while I was out on the road it was Jerry rig to work with and external regulator. As far as I know my harness was kept intact. I am re connecting my original harness with this new alternator. Thx

 

[duncanrm]

I think you need an Auto Electrician at this point.. I have no confidence that your original harness is intact and that you're not running a bit of a dogs breakfast of internal regulation/external regulation wiring. The pinout diagram I have shown above would allow you to hack out a working solution but you need at least some level of knowledge on how to use a test lamp etc.

 

[rideglobally]

I think you need an Auto Electrician at this point.. I have no confidence that your original harness is intact and that you're not running a bit of a dogs breakfast of internal regulation/external regulation wiring. The pinout diagram I have shown above would allow you to hack out a working solution but you need at least some level of knowledge on how to use a test lamp etc.

Ok thank for your help. I am currently in La Spezia, Italy then Genoa, Italy in about a week if someone on the forum can recommend an auto electrician it would be great. Thanks again.

 

[rideglobally]

Can you tell me where the yellow wire is connected in this picture. Is it connected to the battery positive or the ignition. I am gonna by pass my OEM hasness and hack my alternator directly. Is the white wire necessary to get my alternator charging? If it is I will connect the white wire to the OEM harness by using a jumper wire, I am not sure if this part of my OEM harness works. This is a temporary solution until I find an Auto electrician. Thx for your help.

 

[ToyotaMatt]

There are two post on the alternator the white is positive. The other is negative correct? Can i connect the black negative wire anywhere I can get ground (negative) or directly to battery negative. Are these the only two wire connected to these two post? Is there another wire? As you can see I have the original harness that connects to the green plug on top of the alternator. See picture thank you.

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