Alternator going out? "check charging system"

So I searched on this and all the threads end up being either the alternator or the battery, but I see people saying they tested one or the other and found it bad. But my battery and alt tested fine.

This only happens if I get on it so I guess I would say
"under load"? the info center says "check charging system" but it goes away like 5 seconds later... the car is running fine.

Went to vato zone and checked the battery and alternator.
The alt is putting out 14.39v and the battery is at 12.79v.

Alternator STILL going bad regardless of the test results?
The light has come on twice in one week but very random.
I'm not sure if I can repeat the problem myself.

Should I just throw in a new alt anyway? it's an 08 with 68k and the original alt.. battery is 1 year old.

FWIW my alternator and battery went at the same time. I also have an 08. My dashboard was possessed when it happened. All kinds of lights went off. When tested the alternator was putting out 9v.

What do you think the odds are that the new battery is going out?

I'm leaning towards the alt as it's almost 6 years old, but why would it test fine?

Does it just die all of a sudden? I have no check engine lights, no loose plugs etc...

fdjizm said:

I'm leaning towards the alt as it's almost 6 years old, but why would it test fine?

Does it just die all of a sudden? I have no check engine lights, no loose plugs etc...

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Mine did. At first it acted like there was a vacuum leak and died on the highway with all the warning lights going off. I had no warning at all. Replaced the battery and all was good but I kept an eye on the volts. It went down to 12 volts and started the same light crap. That's when I replaced the alternator. So far so good about 7 months later.

fdjizm said:

I'm leaning towards the alt as it's almost 6 years old, but why would it test fine?

Does it just die all of a sudden? I have no check engine lights, no loose plugs etc...

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My battery light came on during my trip to get my Whipple installed back in 08', car is an 06'. Light goes on/off all the time, mostly stays on. Still on original alternator, battery was changed last year. No codes show on SCT tuner, however I had my shop scan it & I have DTC code P0622. Seems to be a short somewhere, never have been able to find it. If it isn't broke then don't fix it. Just my 2 cents, as long as alternator is fine I would leave alone.

Thanks fellas, damn I don't know what to do.
I don't want to get stranded somewhere lol.

I believe the alternator just craps out quite suddenly. Just keep an eye on it but it sounds like it needs replacing broski

IIRC there is a part within our alternator that goes bad with time that the vatozone tests don't pick up. I would recommend changing out your alternator and make sure to get a new one. No rebuilds.

fdjizm said:

Thanks fellas, damn I don't know what to do.
I don't want to get stranded somewhere lol.

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You could buy one and put it in the trunk. If you don't need it return it. I bought a rebuild from O'reilys. It has a lifetime warranty so I figure I'll never have to buy another alternator for the Mustang. It takes about 10 minutes or so to change so I decided to take the risk on a rebuild.

BruceH said:

You could buy one and put it in the trunk. If you don't need it return it. I bought a rebuild from O'reilys. It has a lifetime warranty so I figure I'll never have to buy another alternator for the Mustang. It takes about 10 minutes or so to change so I decided to take the risk on a rebuild.

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I did the same. I also got the 0622 code, replaced the alternator and battery. The only problem was the plug worked loose on the alternator a couple of weeks later and the dash lights went possessed and the headlights "pulsed" rapidly over 4k rpm.
I bent the tab up and made sure it locked. No problems at all now for a couple of months.

I'm going to see if vatozone has the OEM motorcraft alternator.
I will leave it in the trunk with a socket set just incase.

Throttle body comes off to remove the alt right? I put on my delete plates like 3 years ago forgot what it looks like under there.

One diode goes out in the alternator, which makes it test ok but doesn't charge the battery properly. I just went through a whole electrical conundrum with my car. Ford Alternators suck.

Taxman said:

One diode goes out in the alternator, which makes it test ok but doesn't charge the battery properly. I just went through a whole electrical conundrum with my car. Ford Alternators suck.

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This is it! Throttle body doesn't have to come off, just take out the two outboard bolts on the alternator bracket with a small wrench.

Taxman said:

One diode goes out in the alternator, which makes it test ok but doesn't charge the battery properly. I just went through a whole electrical conundrum with my car. Ford Alternators suck.

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Didn't you have a pa alternator?

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durr4456 said:

Didn't you have a pa alternator?

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That was my third one. Now I have one I got at O'reilly's with a lifetime warranty.

I've read good and bad things about PA it's like right down the middle lol.

fdjizm said:

I've read good and bad things about PA it's like right down the middle lol.

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The only thing good about them in my eyes is that American Muscle refunded my money even though it was on my car for 6-7 months.

The electronic testers are junk. Only way to properly check is in car with a good machine. More important that voltage is amperage. Under load there is more amperage draw. If the draw is too large, it can cause the diode to go nuts! I would suggest replacing it now before you get stranded like you think.

I have had that light on for a year now, cant figure out what is wrong. New battery and alt runs fine

My charge light use to come on like that. Set my Aeroforce to watch voltage. Voltage would be 14.x and then suddenly drop to 12 or less and light would come on. Sometimes it was 10 seconds, then it was 3 minutes. Voltage would go up to 14.x again and all would be fine. This went on for weeks. First 3 times the light came on it was every other week or two.

Finally bought a rebuilt from Advance Auto (stamped Motorcraft just like stock one) and it has been fine since- over a year. plus Advance has some great online coupons (big savings) to use and you can pick it up in the store.