voltage regulator or something else

[Full_Throttle]

So my volt meter appears to be telling me I may have a problem. I am somewhat new to the 70 series, so I thought I should ask some questions. I notice that my voltage gauge seems to fluctuate quite a bit at times. At night my headlights and dash lights dim when the gauge drops to the bottom of the "allowable range". My voltage is definitely dropping. Other times it is running at the very top of the range, 16V I believe. Granted I am sure this gauge is not very accurate, but the dimming lights tell the tale. is this my Voltage regulator or a failing alternator itself? Engine is a 3B, in a 1985 BJ73 12V from Australia.
I am assuming I have the internal voltage regulator on my alternator.

What are my options, and where can I get rebuild parts? I am in the States.

Thanks!!

 

[coldtaco]

It’s probably a external voltage regulator? My 85 2H is external regulated, but this doesn’t mean yours is

 

[TonyP]

Your local Vatozone/Checkers/ect can test the alternator for free.
OR
Most auto elecriticans or Starter/Alternator shops can rebuilt your unit if you don't want to source a new one. Many can test them as well.
Depending on the alternator, many times they can up-rate the alternator as well.

 

[Full_Throttle]

After making this post I started thinking that mine may be externally regulated. I have been so stinking busy that I keep forgetting to pop my hood and look

What is the testing procedure to test the voltage regulator? I also have access to a pretty good local alternator shop....so IF I need to be looking at the alternator instead of the regulator I will.

That is kind of my question, does this seem to you guys to be a voltage regulator issue or an alternator issue, and how do I test? (assuming I CAN test)

 

[roscoFJ73]

Regulator part number. 27700-15030 12V 40A, 45A, 50A, 55A

Try googling it and see what you get.

The part is also used on a heap of Corrollas , 3F (non US) 22R and 2L.

These alternators are not cheap and the used units will most likely be high milers. Best to get it checked out . A rebuild would be the best.

 

[roscoFJ73]

That is kind of my question, does this seem to you guys to be a voltage regulator issue or an alternator issue, and how do I test? (assuming I CAN test)

Lots of videos on youtube about this, look for one with a denso alternator (all toyotas), not that it makes much difference.

 

[Full_Throttle]

So I found some great info right here on Mud all about the external voltage regulators....On the 1st page is a good write-up on the 3-wire external regulators...on the 2nd page he gives a great description of the 6-wire ones.

This is great information.

Voltage Regulator (ext.) / How it works