Damn, alternator isnt charging. How to check?

[Greg5OH]

New batteries, starts to crank slow. uhoh, i know alternator didnt charge them last night.
Yup, voltage down to 11.7, hope she starts after work today.

ANyway, regulator is about a year old, (not eliminating its the problem), alternator...probably original.
What should I measure and how many volts should I see?

 

[Greg5OH]

, so oreileys has albulance 100 amp alternator for 95 bucks, 12 bucks for voltage regulator.

autozone, same price on alternator,
get this
voltage regulator
137 dolars. !!!!

 

[theguruat12]

3G 130A at the junkyard for $25...just mentioning. If you want to save a few dollars.

EDIT: At least, that's the price at my local yard. I lost count after 17 of the alternators. I was curious how many they had.

 

[Greg5OH]

I have V belts though.
Also I dont have time to do to JYs. and theryes none local to me.

Definitely want to test to be sure what it is before throwing parts in.
How can I tst the alternator and regulator without removing them?

 

[theguruat12]

Good point, the only reason I feel safe using an old one is that I can have it tested and if it's bad, I have like 20 more to choose from XD

 

[Greg5OH]

is the red or the white terminal on the alternator the field wire?

 

[theguruat12]

Here's the wiring diagrams for an '89, along with a video of all of the external ones in general (identical to my '85):

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http://www.youtube.com/watch?v=KjdaTypqj6o

 

[OLDBULL8]

http://www.bing.com/videos/search?q=How+to+check+an+automotive+alternator&FORM=VIRE3#a

Does your Alt have an internal or external regulator?

 

[Greg5OH]

thanks, im goginto full field it (regulator unplugged right?) and check votlage across batteries.

 

[theguruat12]

Ya just 12V to the field terminal on the alt (reg unplugged) and it should fire off at full output. Did one of those have the right terminals for you? USUALLY the stator would be the white wire and the field would be the red.

 

[Greg5OH]

dont know, havent gone to the store yet. At work till 6. Going to test it in the parking lot on lunch. Hopefulyl just the regulator (thats what it was last time).
12$ for 1 year warranty model
$20 for lifetime warranty model.

probably will spring for the 20$, as it seems they fail on me after 1.5 years

 

[icanfixall]

After burning out 2 external voltage regulaters my favorite mom and pop shop told me to take the battery power off the system and then connect the regulater into the harness and ground. After that I never burned out another regulater. They told me when you ground the regualter and connect the power to it the surge will fry the regulater.

 

[OLDBULL8]

Those damn sheet metal screws don't ground the regulator very good. Rust, corrosion, Michigan Salt and just the air around Pontiac.

 

[OLDBULL8]

After burning out 2 external voltage regulaters my favorite mom and pop shop told me to take the battery power off the system and then connect the regulater into the harness and ground. After that I never burned out another regulater. They told me when you ground the regualter and connect the power to it the surge will fry the regulater.

Gary: Thats about as clear as mud to me.

 

[f-two-fiddy]

He said, remove the neg battery terminals until you completely finish installing the regulator.