Alternator not charging

[Captain Al]

So I got this battery warning light on my dash a while back and then it went away on occasion, now it stays on and the battery/alternator tester, when hooked to the battery, reads barely charging. Could I have a bad alternator or is there someplace else to look first? 06 w/22k miles Thanks for any help.

 

[86GT351]

Could be battery, Alternator, Wiring or Smart Junction Box. Check your smart junction box behind the passenger lower kick panel for water intrusion. If it has there are 2 drains under the hood that are rubber. Remove them to make sure all the water is draining out of the car.....Not in the car.

 

[DieHarder]

First things first. Recharge the battery. Check/clean connections to the alternator. Check/remove/clean the passenger strut ground and engine grounds. Make sure the battery positive/negative terminals are clean. Use a VOM to verify the alternator is charging. Alternator charging is handled by the PCM. If it's not showing above 14v the alternator is the most likely suspect. Then, I would look for any corrosion in the battery and/or ground cables. You can get OEM battery cable replacements. Replaced mine and saw a +1v rise in voltage measured across the terminals.

 

[Captain Al]

Thanks Guys, I had already cleaned and checked the battery terminals, Checked fuses, and took a look at any evidence of water intrusion at the psgr side kick panel. All appear to be fine. I recently purchased this car from a dealer online, and of course they cleaned the engine bay. Could having water/cleaning products used on the engine have caused my problem? I think I could remove the alternator by accessing the air intake, and I figure that if I go that far to check the main battery supply cable I might just go ahead and remove the alternator to have it bench tested. At this point, My meter reads just over 12V with the engine running at idle with a fully charged battery. Is there anything else I should check? Thanks

 

[07 Boss]

Our alternators are notoriously bad, I went through 4 or 5 before I finally put a 2010 alternator in there and it's been fine sine.

 

[DieHarder]

Thanks Guys, I had already cleaned and checked the battery terminals, Checked fuses, and took a look at any evidence of water intrusion at the psgr side kick panel. All appear to be fine. I recently purchased this car from a dealer online, and of course they cleaned the engine bay. Could having water/cleaning products used on the engine have caused my problem? I think I could remove the alternator by accessing the air intake, and I figure that if I go that far to check the main battery supply cable I might just go ahead and remove the alternator to have it bench tested. At this point, My meter reads just over 12V with the engine running at idle with a fully charged battery. Is there anything else I should check? Thanks

I would suggest testing the alternator. Most likely suspect at this point. If you want an accurate test of its' condition take it to an alternator shop vice parts store.

 

[Pentalab]

Thanks Guys, I had already cleaned and checked the battery terminals, Checked fuses, and took a look at any evidence of water intrusion at the psgr side kick panel. All appear to be fine. I recently purchased this car from a dealer online, and of course they cleaned the engine bay. Could having water/cleaning products used on the engine have caused my problem? I think I could remove the alternator by accessing the air intake, and I figure that if I go that far to check the main battery supply cable I might just go ahead and remove the alternator to have it bench tested. At this point, My meter reads just over 12V with the engine running at idle with a fully charged battery. Is there anything else I should check? Thanks

I measure 14.75 vdc right at the battery terminals...with eng on idle. If u measure just a bit over 12 vdc, your alternator is toast. This is on my 2010 GT.

 

[Dino Dino Bambino]

At this point, my meter reads just over 12V with the engine running at idle with a fully charged battery.

If that's all you're getting with no electrical loads such as the cooling fan, infotainment system, AC, or lights, the voltage regulator inside the alternator is defective.
Your best options are:

1. Rebuild your existing alternator. This is your cheapest option.

https://www.maniacelectricmotors.co...08-gt-mustang-regulator-brushes-bearings.html

2. Buy a remanufactured OEM 05-08 Motorcraft or remanufactured 09-10 Denso alternator from Ford. Rockauto.com also has them in stock so you can compare the prices.

3. Buy a brand new 160 amp hour PA alternator. This is the best option if you need an upgrade from the OEM 130Ah unit to power a larger amplifier or subwoofer.

 

[whitmanink]

as dino said rebuild ,, i did ,, and its still working like a charm over 1500 miles later

 

[VGMStudios]

If you are going to replace it, buy a 2010 Denso Alternator. They are built better and give more output. The g6 alts in our cars are utter garbage. Don't bother getting another 05-09 alt.

 

[JC SSP]

Many years ago, I used PA alternators thinking they were something special, but had the same decent results as an off-the shelf NAPA replacements, so if you need something quick and with a warranty, they are OK... Try the rec 2010 Denso, seems to work well for everyone.

For the last 15 years I have an electrical expert in my area who does all my alternators. My 05' GT runs a custom rebuilt 200AMP High Output Alternator with 4-gauge power wire and in-line 250AMP fuse. So far no issues...

 

[bambam 06]

I have the Mitsubishi 200 amps alternator used in the Ford Interceptor police vehicles,no problems. They are HD as the police vehicles have a lot of equipment. (computers, lights, sirens etc.