This problem is with my 96 Mustang GT but its my only running vehicle and I need it to get to work this weekend so please help. After about 15 minutes of driving yesterday all of the sudden I have no battery and my car dies. Car was jumped after charging off other cars battery for a few minutes. So I think okay my alternator is gone, not toooo big of a deal. But when I got in the car about 5 hours later im expecting it not to start at all but I end up driving it for ten minutes without issue. Then after sitting for another 24 hours I drove it for 45 minutes without issue with the battery guage on the dashpod reading right in the middle where it always has(middle of 8 and 18). When I come to a stop though the needle drops from about half way to about 3/8 of the way but then stops. I can't remember how old the battery is and the sticker that shows the date of the battery has come off. I havent stuck a meter on the battery yet but other than doing that I don't know what to do.
Also for the last few months my subs havent been working at idle if any other accessories are running which is usually my heat. When this started happening I actually kind of suspected my alternator but the opinions of a few friends said otherwise and I just kind of lived with it. Any help would be greatly appreciated.

 

The alternator has failed!!!!
It is producing the voltage but not the amperage to sustain the operation of the vehicle.
A load test should be done to convince you.
Most parts stores can do an in vehicle test.
A bench test could show that it is operational but the load test is necessary.
Been there done that.

 

I tend to agree that the alternator is bad. Probably failed like some of the older GM's -- a diode trio is bad. Don't know if you can get parts like that any more.

On my old GMC van, I could tell when I was in trouble because the ammeter would stay just on 0, or drop a fraction when I turned on a load.

If you end up getting an alternator, do yourself a favor and charge the battery before you fire it up. It's usually not an issue, but if the batt is low, it will be putting a big load on -- COULD cause damage.

Good Luck,

hj

 

I had a similar problem with my SD just a couple weeks back. My volt meter read normal and my charge light did not come on but every couple of days my truck had a dead battery. I jumped it drove home and charged it up. fine for my short drives to work but days later dead again.

Load tested the battery and it was OK, load testing the alternator showed failed. Replaced the entire alt and no issues since. I think the regulator was sticking causing drain when the truck was off.

Most auto part stores or shops can do these simple tests and they should do it for no charge.

 

New alternator installed and everything is fine now. Thanks I love when things are this easy to fix lol