Alternator not charging

[mep1811]

I have a 1977 FJ40 and the alternator stopped charging. I get a rebuilt alternator and nothing happens. I come to find out the PO had cut out the harness to the voltage regulator.
I've been told the alternator will not work unless connected to the voltage regulator . OK, but then why did the old alternator work just fine for the 14 years I've owned the Land Cruiser?

Thanks in advance for your help.

 

[php74]

Are you positive your battery is still good?

 

[Solace in Solitude]

Are you sure your old alternator wasn’t internally regulated?

 

[S4Cruiser]

Are you sure your old alternator wasn’t internally regulated?

Ding ding!!

 

[Steamer]

Are you sure your old alternator wasn’t internally regulated?

Yup! if your old one ran fine for 14 years without a VR then it must have been internally regulated.

 

[mep1811]

Are you positive your battery is still good?

batteries are good

 

[mep1811]

I took the old alternator to an electric shop to have it rebuilt. It could not be rebuilt and the owner confirmed the old alternator was externally regulated.

 

[Solace in Solitude]

Well, you have two choices:

1. External Regulator: you said you’ve never had one, because a PO removed the regulator harness.

2. Internal Regulator: Expert says your old alternator wasn’t internally regulated.

You said the old alternator charged for 14 years.

Someone is wrong.

 

[Steamer]

Are you sure the regulator shown in your pic is disconnected?
I would trace back the two small wires on the alternator and see where they go.

This diagram shows where they're supposed to go.

 

[Coolerman]

Looking at the back of the alternator where the three pin connector should be you have two wires plugged in. White/Green with a red crimp on and a White/Black with a blue crimp on.
It appears you have those two wires reversed. White/green (this is the FIELD wire from the regulator ) should go to the bottom left terminal and the White/Black (This is a ground wire going back to the regulator) should go to the top terminal. Just swap those two wires and it should charge fine.
The other pic shows that your regulator is still connected to the main harness. The regulator COULD still be bad. If swapping the wires does not get the system working you should then check the regulator.

I have the correct three pin connector that will plug into that alternator. Part # FLF3P6.3B $2.55 and includes 3 terminals.

 

[mep1811]

Looking at the back of the alternator where the three pin connector should be you have two wires plugged in. White/Green with a red crimp on and a White/Black with a blue crimp on.
It appears you have those two wires reversed. White/green (this is the FIELD wire from the regulator ) should go to the bottom left terminal and the White/Black (This is a ground wire going back to the regulator) should go to the top terminal. Just swap those two wires and it should charge fine.
The other pic shows that your regulator is still connected to the main harness. The regulator COULD still be bad. If swapping the wires does not get the system working you should then check the regulator.

I have the correct three pin connector that will plug into that alternator. Part # FLF3P6.3B $2.55 and includes 3 terminals.

Thanks I will do that tomorrow and let you know what happens.

 

[Coolerman]

Great, let me know if you need the alternator connector so you can eliminate a potential short with those crimp on connectors.

 

[mep1811]

Thanks I will do that tomorrow and let you know what happens.

No change. I'm not going to be able to play with this for a couple of weeks.

 

[mep1811]

I did find this connector that looks like it comes off the voltage regulator.

 

[Solace in Solitude]

Your VR and connector is in your first picture, in your first post.

IIRC the connector in your latest post is for the horn... I’ve changed to an air horn and changed connectors, so I can’t validate that.

It’s possible, assuming your VR is actually connected properly, that your VR needs to be adjusted.

Rudi (@bj40green) has everything you need here -> Voltage Regulator (ext.) / How it works

 

[mep1811]

Thanks

 

[mep1811]

Got back home and will dive into this project again. To change directions a bit, is there a bolt on internally regulated alternator that will fit? just thinking if I can make a an upgrade that would be worthwhile.

 

[mep1811]

Found the culprit.

The engine fuse had blown at some point so once replaced it no issues.

 

[Lucille]

in the first pic, you have a big red wire on the stud on the alternator back side, where does this wire go? Directly to the battery? Also i see the thick white/blue stripe wire as part of the harness with the two smaller wires. Where does this wire go?

On my 74, the thick white/blue wire has a ring terminal is on the stud where your red wire is. I am also got getting the alternator to not charge the battery. Alternator and voltage regulator are new in my case.