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Discussion Starter #1
The past two weeks, I've noticed "Check Charging System" has been popping up randomly when I start my car. It'll reset my trip distance as well, and usually goes away when I restart the car. Tonight, while driving, the battery light randomly lit up, and it read the error again. The needle for the battery gauge was going from about 1/3 to 2/3, and whenever it went up, the light would disappear...

Could this be a faulty alternator? If not, what else could it be? It just recently started doing this.
 

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Discussion Starter #3
Damn... that's an unexpected hitch. Just for reference, this also started just a few weeks after I tuned my car. I recall reading somewhere it could do with the RPMs? Could the tune be affecting how the alt is working?
 

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Discussion Starter #4
Update: It's not the alternator. I went and got it checked by AutoZone, and they said everything ran fine and passed all tests.

Could it be a short? I'm still thinking maybe it's tune related.

As previously mentioned, it only started happening a little while post-tune, and usually more-so on cold starts.

I do know that the ford dealership said one of my rear bumper lights (the small rectangular light on the side of the car) had a burnt out bulb, and that the serpentine belt had a crack in it. Could these be affecting it (serpentine belt has never been replaced, car is at 90k miles)?
 

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They have to test the diode. Well really they don't have too, I can tell you right now what is going to happen...




This battery light will come on again and again, it may or may not become more frequent, but it will continue until you swap your alternator. If you let it go on long enough your traction control light, you know the little squirrelly car on your dash, will come on for no reason. Shortly after that you will lose some or all of your dashboard gauges. You may even have some more dash lights come on. Your radio will go dead sometime during this sequence of events. Then your car won't start because there's no juice in your battery. Than you will have to change your alternator for sure. And you might have to put a new battery in too because the shitty alternator put too big of a strain on it. You can only drain a battery so far down and charge it back so many times before it loses it's ability to hold a charge.

Ask me how I acquired this little bit of wisdom.....
Well I'm on my fifth alternator in basically 3 years.
 

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Discussion Starter #7
Damn... I was really hoping it would just be something as stupid & simple as the serpentine belt. But as long as it's not some obscure, difficult-to-fix short, I'm fine with fronting the $200 for an alt.

Should I be ordering anything special, or can I Just pick up the belt & alt from AutoZone? I don't need any high performance alt as far as I know... I'm not running anything beyond stock electronics.
 

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Either get something with a lifetime warranty at your parts store of choice or order the one off of Americanmuscle
 

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When mine went bad I had it tested at autozone and it passed. I took it to the dealership the alternator failed and they replaced it under warranty.
 

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mine comes on sometimes. has not came on in about 6 months now. im going to leave it alone until it comes on more often. i have already replaced my battery once though. just completly died over night for no reason and wouldnt hold a charge after that.
 

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Discussion Starter #11
When mine went bad I had it tested at autozone and it passed. I took it to the dealership the alternator failed and they replaced it under warranty.
I'm no longer covered by the warranty, unfortunately.

I ended up replacing the serpentine belt for a quick and easy $40. The old one was really slick and frayed. Got the new one on, went for a 20 mile drive, and no light or anything... so far. Going to keep my fingers crossed and see if it pops back up.

Cleaned the throttle body too, as an added bonus. The car drives so much better now, can't believe I haven't done this sooner:dunce:
 

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Update: It's not the alternator. I went and got it checked by AutoZone, and they said everything ran fine and passed all tests.

Could it be a short? I'm still thinking maybe it's tune related.
Like it's been said before... it's the alternator. Read my build for my struggles with the same issue. It's a known issue that the diodes go bad. The alternator will test good, but kill your battery.

I'm on alternator number 3 and battery number 3. I finally went with the PA Performance alternator from AM. I also got the upgraded wiring kit for it. Haven't had a problem since.

Make sure whatever you buy, it's new and not re-manufactured.
 

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same issue

i have been having the same issue. i just replaced the alternator and battery 2 weeks ago and it is still doing the same exact thing that you described. i have gone through 4 alternators so far. do you have any idea what the root cause is?
 

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i have been having the same issue. i just replaced the alternator and battery 2 weeks ago and it is still doing the same exact thing that you described. i have gone through 4 alternators so far. do you have any idea what the root cause is?
I once had a new alternator put in at the dealership under warranty and that one was bad too. Had to wait another day for them to get another one in. There are a couple of reasons why these alternators suck. First off I don;t think you can find a new one, they are all rebuilt or refurbished. I happen to have a new one in the box but I'm not parting with it. It is my back up spare that I keep on hand even though I switched to a 2010 alternator. That is the second issue is that our cars came with a single phase unit which sucks and nobody really uses them any more. They switched to a 3-phase unit in 2010. It should bolt right up so if you get a new alternator, get a 2010 one.
 

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That is the second issue is that our cars came with a single phase unit which sucks and nobody really uses them any more. They switched to a 3-phase unit in 2010. It should bolt right up so if you get a new alternator, get a 2010 one.
AFAIK, all modern automotive alternators are triphasic. The original 05-09 alternators were simply poorly constructed. Replacements from the dealership are remanufactured, but I don't know if Motorcraft used better materials.
The 2010 seems to be the best replacement, and being Japanese (Denso) it might also be more reliable. Time will tell.
 

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I had the same issue and after having the alternator tested a couple of times, alternator cable replaced, and put a new sense wire on, it turned out to be the alternator fuse loose in the distro box. I could push it in and after about a week, it would vibrate enough to cause the "Check Charging" light to go on and off.
 

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I replaced the wire that connects to the back of the alternator because the father in law broke the locking mechanism. It took care of that issue and now I am having issues with something squealing when I accelerate.
 
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