Anyone know where a voltage regulator is located?

I have a 1987 Nissan sentra that needs a new voltage regulator. Does anyone know were the voltage regulator is located on the car?

The voltage regulator is located inside the alternator. When the voltage regulator fails the entire alternator is usually replaced.


It should be on the alternator or internal to the alternator. There will be an oblong plug for it so just look for the connecter. If its internal, just buy the whole alternator.

I agree. If you want to replace just the regulator, you’ll be doing an additional 30 minutes or more of work, just to save a few bucks.

Not only that, but most parts stores won’t have the regulator in stock

The only thing I will add is that if you don’t know where the voltage regulator is located then why do you think the car needs one?

Your car needs the whole alternator by now. The closer you get to 250,000 miles the more likely you get to a common failure point for Japanese alternators. They are reliable but sometimes they get old too.

Thanks for the help.
The reason I believe that my voltage regulator is going out is because I have a charging light that comes sometimes then goes off. Also, I have a dimming of lights, that comes and goes. Yesterday, I had my alternator tested and it passed (the alternator is sorta new - its about 3 years old). So, my thought was it must be the voltage regulator. I believe the voltage regulator is separate in this model of car - I am not positive. With that said, would it be better to replace the alternator?

Thanks again for all the advice and help, everyone.

Did they test the alternator while it was in the car, or did you take the alternator to a shop to have it tested? Either way, the regulator looks like it’s inside the alternator, so it was also tested:

If the alternator/regulator is ‘good’, then it’s either the battery, cable connections, cable, or a bad ground connection. With a 27 year old car it could be any of those.

Buy a quality alternator rebuild. Sometimes they don’t even change things like regulators, brushes, bearings, diodes and just test them. So who knows what’s wrong?

Before you get into anything else, make sure your fan (or serpentine) belt isn’t slipping.

Yes, the alternator was checkered on the car with the battery . Texases, how do you know that regulator is in the alternator?

Bing, As far as I know, I bought a good quality alternator about 2 or 3 years ago from NAPA . Would you consider that a good quality part?

Marketmast, how would I know if my belt is slipping on the alternator? Would a slipping belt be making a occasional squeaking noise? Once warmed up goes away. And in heavy traffic when using brake a lot … the alternator would vibrate a lot.

Thanks again guys attempting to help me.

The photo of the regulator shows that it is part of the alternator, with the two brushes (the rectangular parts sticking up into the round opening) that are part of the assembly.

Squeaking noise from the belt means it’s slipping. The belt might be loose, or worn out. How old is it?

If they tested the alternator on the car, that includes testing the regulator.

I have had mixed results with Napa remanned alternators. In my experience, they tend to fail after a few years

Nothing against them but I quit buy Napa alternators when even the new ones would start acting up in a year or so. I only get Delco now but haven’t needed one for years.

Texas, thanks for explaining that. I now understand, why I can not locate the part. How would I know if my belt is slipping? The belt is about 3 maybe 4 years old. The squeaky noise comes and goes, I can not locate it. It shows up generally when it is damp outside but lately, ( last 2 or 3 months it has been a persist after starting my car. After the car warms up the squeak goes away. The pattern from the light coming on,is after driving my car a steady speed like on the highway or just on a back road then come to a stop, the charging light, oxygen sensor, and the brake light all come on.

db4690, how many years would you say is the lifespan on a napa alternator?

Bing, I understand your point. What company is Delco? Do they carry parts for old car from the 80’s?


In my experience, Napa alternators don’t last more than 5 years

db4690, would an alternator test perfect when tested if it is not performing currently?


I’ve seen many junky rebuilds that perform perfectly one day, then don’t work the next day

This sometimes goes on for quite awhile before it quits entirely

Anyways . . . how old is that battery? Has it been tested?

yes, the battery has been tested its a 48 month battery about 3 years old. The battery tested fully charged and in perfect shape. This just makes my problem that much harder to track down! Thanks again for your help!

I’d concentrate on the belt, the connections, the cables, and the battery before thinking about replacing the alternator. If you’re hearing squeaking, the belt is either loose or worn out, if it’s been a while I’d replace it and adjust it correctly.