Is my 1995 GMC Sierra Ext Cab 5.7 V8 Alternator Dying?

[Bri]

I have noticed that my battery gauge has been showing around 12 after it's been running for a while. When I first start it, it is right at 14. I don't put on any accessories except for daytime running lights and drive it on the highway. The gauge just goes down to 12 and stays around there. When i turn on signal lights the battery gauge dips for a half a second and goes back to 12. RPM's don't seem to change battery gauge. I just went and got a new battery with 100 more Cold Cranking Amps and that seemed to make the gauge dip less but same result. Is this my alternator or is possibly something else in the charging system? I started the truck and took the battery off and it drove it around and it worked the same without the battery. Is this an indication of something that should be fixed right away or can I continue to drive it as is? Any information would sure be great, as I really can't afford to go putting $100 parts to not fix the problem.

Thanks Bri

 

[bandit_60]

sounds like it could be the alternator. sounds like the brushes are worn in the alternator. it,s still drivable as long as the battery stays charged. here,s an idea. see if you can borrow a alternator just to try and if it fixes it you can buy a new 1.

 

[Mr. KnowItAll]

14.8 volts is normal during idle.
Anything less, replace your alternator.

It's 15 years old

 

[Mr. KnowItAll]

14.8 volts is normal during idle.
Anything less, replace your alternator.

It's 15 years old

 

[Jaime]

Sounds like your alternator, but to be sure if you have a voltmeter check the volts on your battery to rule out a bad gauge.

 

[jagtoes]

I would pull the alt. and take it into an autozone or other type store and let them do a quick test. This doesn't cost anything and they will tell what is wrong. It sounds like the regulator is gone but have them check it out. If it is bad diodes then you would be better off buying a rebuilt or one from a salvage yard.