Alternator Light flickering

freedom5 · Oct 6, 2015

The other day my charging light started flickering. Usually starts after the engine warms up. Light goes out above 1500 RPM. I took it to Auto Zone where I had recently purchased a new battery and the battery checked O. The clerk suggested I check the plug ins on the alternator. Cleaned them and still have the problem. I believe the alternator needs replacing. Any suggestions.

Haywire6000 · Oct 6, 2015

If it goes away like clock work at a 1500, more then likely a bad alt.

txgocartB3000 · Oct 6, 2015

While you were at Autozone you should of gotten an electrical system check.

Would of known then if alt was bad.

Ray

freedom5 · Oct 6, 2015

txgocartB3000 said:
While you were at Autozone you should of gotten an electrical system check.

Would of known then if alt was bad.

Ray

I had bought a new battery 8 months ago at Auto Zone so I went there to have it checked. They had a female on duty who went out and checked the battery. She said the alternator showed bad. I went back later to purchase a new one and the male salesman said I should check the plug first as most failures were not the alternator. I pulled the plug and washed it out with contact cleaner but still have the problem. I'll take it a different Auto Zone and see what they say. The alternator is an old one and not worth rebuilding.

Freedom5

adsm08 · Oct 6, 2015

I am going to go ahead and take issue with a few things in that post.

1) I have seen many many bad alternators in my time working on cars. Even the number of ones bad out of the box is high. I can count on one hand with fingers left over the number of bad connections I have seen cause a problem.

2) I object to your need to classify the advice you got by the gender of the individuals giving it to you. I know a lot of women who are extremely capable of working on cars and I have worked with a lot of men who have their heads shoved so far up their asses they can't tell a spark plug from a lug nut, but they still get up and go to work every day to fail miserably at fixing cars.

freedom5 · Oct 6, 2015

Sorry you took offense. I didn't bad mouth the female - I said she told me the battery was good and the alternator showed bad. All I said about the male salesman was that he suggested I tried cleaning the plug first.

You have been well known for your expertise for several years. I'll chalk your response up as you having a bad day.
F-5

buddieboy · Oct 6, 2015

freedom5 said:
The other day my charging light started flickering. Usually starts after the engine warms up. Light goes out above 1500 RPM. I took it to Auto Zone where I had recently purchased a new battery and the battery checked O. The clerk suggested I check the plug ins on the alternator. Cleaned them and still have the problem. I believe the alternator needs replacing. Any suggestions.

belts not slipping is it but in the altonator the main thing causeing them to fail is the brushes as they can get a little oil or grease from old rear bearin seal after that the residue quickly turns to a ultra thin layer of varnish /ect then the charge voltage cannot connect through sometime sanding th slipp rings and the brushes with some 400 wet and dry is all thats nessesary provide you know how to do the disasembley and polish the slip irngs and brushes obviously if the brushes are all the way worn then thats differant thanks

freedom5 · Oct 7, 2015

Haywire6000 said:
If it goes away like clock work at a 1500, more then likely a bad alt.

I took it to a trusted shop this morning which has a full diagnostic capability. It is a bad alternator. I am having it changed at this shop. At 82 I didn't feel like messing with it. I've had the truck for 28 years and usually maintain it myself but it's getting more difficult.

Thanks to all who submitted HELPFUL SOLUTIONS.

Freedom5

Denisefwd93 · Oct 7, 2015

I'm watching this one! ASM :icon_thumby:

enjr44 · Oct 7, 2015

Most likely a failed diode in the Alt. It still produces enough voltage to turn out the light above idle; but, not enough at low idle.

And at 82, I don't think I would fool with it either. I'm 72 and have started having more stuff done. Most difficult thing I have found about that is trusting the shop to do it right.

Denisefwd93 · Oct 7, 2015

From working on my boat I learned enough about Alts to be dangerous. But isn't the light on the "field" circuit? ? We went to a self exciting alt on the boat.
I remember generators on cars from the 50s.. yeah.. that old I am :bawling:

freedom5 · Oct 7, 2015

enjr44 said:
Most likely a failed diode in the Alt. It still produces enough voltage to turn out the light above idle; but, not enough at low idle.

And at 82, I don't think I would fool with it either. I'm 72 and have started having more stuff done. Most difficult thing I have found about that is trusting the shop to do it right.

I'm an old retired Master Army Aviator and the shop I took it to is owned by a former helicopter crew chief. I've had work done there before and trust him.

Thanks for the comment.

Freedom5

enjr44 · Oct 8, 2015

freedom5 said:
I'm an old retired Master Army Aviator and the shop I took it to is owned by a former helicopter crew chief. I've had work done there before and trust him.

Thanks for the comment.

Freedom5

And thanks for your service. I am a retired AF SMSGT.

pjtoledo · Oct 8, 2015

Well, my 62 years doesn't even come close to some on here.
the good news is that "Ranger Fever" might last another 20 years for me.

kimcrwbr1 · Oct 8, 2015

You can be a parts changer or you can do a proper diagnostic. It could be a bad battery. Just because its new dont mean sqwat.

Alternator Light flickering

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