Quick questions on my '94 Alternator

[jdjonesdr]

Messing around with the alternator I found a couple of things:
My alternator is putting out 12+/- volts. I get the same reading at the output on the alternator and the battery. It should be 13+, correct?
(The battery is a new Interstate and charges to 13+ with my charger.)
If I turn on the lights and A/C, the voltage drops to 11. No bueno.
After looking at it a little closer, the first thing I can see is that is it old and probably the original one.
The pigtail connector is in bad shape, and when I look at it a little closer, it only has one black wire in the wire cover. It also doesn't latch correctly on the alternator.
Since I am always one to overreact, I decided to buy a new original AC Delco alternator, the rubber cap for the output terminal, and a new pigtail.
Stupid question, but I'm on the right track, correct?
The only thing that puzzles me is the single wire coming from the pigtail. Does that make any sense?

As always, thank you in advance for your comments/advice, and Happy New Year.

 

[someotherguy]

Should be charging very close to 14V running. If the harness connector isn't good, the alternator may not be kicking in. I've fought a couple that would charge intermittently and when they'd stop, wiggling that connector would kick them in and you'd notice it immediately as a change in pitch of the alternator and idle speed.

I'd address the connector first, before replacing the alternator.

Richard

 

[jdjonesdr]

Should be charging very close to 14V running. If the harness connector isn't good, the alternator may not be kicking in. I've fought a couple that would charge intermittently and when they'd stop, wiggling that connector would kick them in and you'd notice it immediately as a change in pitch of the alternator and idle speed.

I'd address the connector first, before replacing the alternator.

Richard

Thanks, Richard.
That was my first thought, but everything there is pretty deteriorated. The Alternator is downright ugly.
Also, did all of the wiggling (but not disconnecting while running) and can't get a noticeable variation in voltage/sound/etc. Everything else is tight.

 

[NorwegianViking]

It does not take alot of resistance for the voltage to not be optimal. I would go over all the connections with some sandpaper. Even tho if the connections are new just a small bit of oxidation would be enough. I tend to use some kind of electrical spray.

Maybe open up the alternator and look if the winding is ok, if its shorted close the output that could be the reason.

Happy new year.

 

[FullBlowncustoms]

Add extra grounds also, or check the ones you have at battery to body, motor to chassis etc... My old 95 K1500 did the same thing with new Alt, then I added grounds in places. And the belt tensioner also check. My 95 is one wire also, plus the large hot cable.

 

[FullBlowncustoms]

On my 95 winter truck I have one ground going to the fender from battery, then from battery I have the large ground going to the front exhaust manifold bolt beside battery, On that same bolt I added a ground to the frame under that bolt. Then I added a ground on that same side of frame to a bolt stud on the manifold drivers side. No Idea what that stud was for originally LOL... Then my new Alt I put in work again... May not be your problem but it fixed mine with the new Alt, probably because mine is rusty winter driver, and the extra grounds fixed it. But if as ugly as you say? replace the alt with new one LOL... OH... is your original alt SINGLE wire ???

 

[jdjonesdr]

On my 95 winter truck I have one ground going to the fender from battery, then from battery I have the large ground going to the front exhaust manifold bolt beside battery, On that same bolt I added a ground to the frame under that bolt. Then I added a ground on that same side of frame to a bolt stud on the manifold drivers side. No Idea what that stud was for originally LOL... Then my new Alt I put in work again... May not be your problem but it fixed mine with the new Alt, probably because mine is rusty winter driver, and the extra grounds fixed it. But if as ugly as you say? replace the alt with new one LOL... OH... is your original alt SINGLE wire ???

The alternator is probably the most ugly thing under the hood, but truth be told, it doesn't look THAT bad, it just doesn't look as good as everything else.
The truck only has about 33k miles on it.
I like grounds too. I have a '90 Cherokee XJ that begs for them. lol

 

[GoToGuy]

GM one wire alternator normal. Pull the alternator have it checked at AutoZone or O'Reilly's, or your choice parts place. If you just want to cover all your bases. Can be shiny and dead. Looks like puke but still a workhorse. Electricity is funny like that.
Not at work ,holidays so went to AutoZone watched 'em spin up one I had on shelf. Sounds good good volts. Install on 95, so I can rebuild the squealer.

 

[FullBlowncustoms]

Back in the old days LOL, 70's.... I use to just replace the reg in the alt. Was a small pin hole on back side to slip in a paperclip to hold the 3 brushes etc...in place LOL..

 

[Schurkey]

My alternator is putting out 12+/- volts.

Almost certainly a failed alternator.

I get the same reading at the output on the alternator and the battery. It should be 13+, correct?

As said...14.x is typical.

The pigtail connector is in bad shape, and when I look at it a little closer, it only has one black wire in the wire cover.

Yup.

I decided to buy a new original AC Delco alternator, the rubber cap for the output terminal, and a new pigtail.
Stupid question, but I'm on the right track, correct?

Absolutely.

The only thing that puzzles me is the single wire coming from the pigtail. Does that make any sense?

OH... is your original alt SINGLE wire ???

Of course not. I expect it's a normal CS130, with a single small-gauge brown wire in the "P" socket of the molded-plastic connector on the side, and another, heavy output wire on the back. Two wires, total, plus a ground connection via the case.

"Single wire" alternators in the 10- or 12SI series had only the output wire, no external wires at all at the regulator.