Alternator Question

[NotJLB]

This is not about our Yukon or our Escalade, but you guys are so much more fun than those on Mitsubishi forums, and I suspect my question is common, so here's this, for my '03 Mits Eclipse.

I know that when the battery and brake idiot lights come on together, it means the alternator is not charging the battery, but can something else be causing it . . . a loose wire, or . . . . ?????

At rest, my battery's fine, 12.6-ish, then the lights come on and I hope to just be able to get where I'm going. Most of the time, the lights go off, and when I get where I'm going, and check my battery, it's OK. 12.6-ish again.

Yesterday when the lights came on, I pulled over and checked the battery with the idiots light on and engine running, 12.26 and falling.

Made it home, and this morning it's 12.6-ish again.

I'm driving our Escalade until I figure this out. There, feel better, I said Escalade.

 

[Doubeleive]

if you go by autozone, o'reilly's etc they can test it for free, I would think with the engine running you should be getting at least 13v+

 

[drakon543]

is it 12.6 with the engine off or running? with the engine running it should be higher than that.

 

[iamdub]

Normal charging for an alternator with no/minimal load is 14.4 VDC. With 12.6, either you have a heavy load (A/C on MAX, both cooling fans running, maybe a stereo bumping...) or a weak connection from the alt to the battery or a weak/dead alt.

 

[NotJLB]

OK, I'll try again.

I had to go to the post office, about three miles. I checked the battery before I left, engine off, and it was 12.6. Then I checked it with the engine running, and it was 14.5.

So far, so good.

On the way back from the Post Office, the idiot lights came on. Other than stopping to help a turtle across the road, I came straight home. I got out and checked the battery, idiot lights still on and engine running, 12.26 and falling.

I shut the engine off and checked the battery, 12.5.

So, if I take it anywhere, and they check it with the idiot lights off, it will check out fine, but if the idiot lights are on, it won't . . . same as I'm doing.

My question is is this typical for an alternator going bad, that will be working, then not be working, then be working, then not be working?

 

[Doubeleive]

OK, I'll try again.

I had to go to the post office, about three miles. I checked the battery before I left, engine off, and it was 12.6. Then I checked it with the engine running, and it was 14.5.

So far, so good.

On the way back from the Post Office, the idiot lights came on. Other than stopping to help a turtle across the road, I came straight home. I got out and checked the battery, idiot lights still on and engine running, 12.26 and falling.

I shut the engine off and checked the battery, 12.5.

So, if I take it anywhere, and they check it with the idiot lights off, it will check out fine, but if the idiot lights are one, it won't . . . same as I'm doing.

My question is is this typical for an alternator going bad, that will be working, then not be working, then be working, then not be working?

sounds like the alternator is going bad to me

 

[NotJLB]

Me, too.

Just wanting to hear it from someone I respect more than me, like a stranger.

 

[drakon543]

alternator or a poor connection from the alternator to the battery as stated above. actually when originally bought a g6 i used to have i had it for about a week and the battery light started sporadically coming on. now shame on me for not doing a more thorough inspection myself but i expected more from a reputable dealership from a car off thier top front line cars. previous owner had installed a grounding/ charging wire kit or something. used the wrong battery stud for the positive and it was just flopping around.

 

[iamdub]

alternator or a poor connection from the alternator to the battery as stated above.

This. Next time it's running and the warning lights come on, have someone watch the lights and gauge while you slowly move the charging wires under the hood and have them tell you right when the voltage climbs. You may have to tap on the alternator case with a large screwdriver handle or something similarly heavy but non-destructive. Could be a circuit inside the alternator opening when hot or a loose charge cable. Make sure your engine ground is clean and solid. Make sure ALL grounds and positives (starter included) are good.