CobraStangGT16

Hey guys. title says it all. I was just coming home and my battery light popped up. It would turn off when I came to astop, but then back on at speed. Then when I came home, it stayed on while I was parked. It cranks fine, and everything works OK.

Earlier today, my cars battery died from having the music on too long with the car off, so we push-started it cuz we had no other cars or jumper. It started fine, no light, nothing, and I drove it to the mall and back and it was fine with nothing on.

What could it be? Just an old battery? My dad said thewater level may be a little bit low, butI want to make surethat that could throw the light.IREALLY hope it's not the alternator...

Thanks.

SlvrOhTwoGeeTee

Maybe your alternator is flaking out... but you should be able to take it to AutoZone or your local parts store and get your charging sys and batt checked for free. Then you will know for sure.

CobraStangGT16

That doesn't seem like something that happens to Mustangs very often though...the battery is an old Duralast, and I wouldn't stop to think that it was over 4 years old at least. I've only had the car for a year with no problems...

any connection with the battery dying and push-starting it today?

CobraStangGT16

I was going to try that for sure anyway, but I wondered if this had happened to anyone here before.

I'll take it to autozone tomorrow.

ShadowDrake

A loose connection to the alternator can cause this problem. Had it happen with our V10 excursion... battery light would be on sometimes, off others, would flicker at times... but it never had any electrical problems (starting, lights, charging, etc). Checked the alternator and the plug was starting to come loose and was causing the battery light to come on. Just go get your alternator tested, it's free and will rule that out.

Pitt

Since you didnt jumpstart, your alternator had to work overtime to charge your battery or keep it on life support. The weird thing is your battery light goes on when your RPMs rise (if I understood correctly). It should be the opposite....is your belt slipping? Doubt it, if not you wouldve overheated too. Its probably a bad battery though. Sorry I was of no help whatsoever, good luck though.

CobraStangGT16

Drake, I'll check the connection as well.

Pitt, how is it that the alternator was working as life support? Whenever I jump start it, I just remove the jumper cables from my battery as soon as the car starts. I just leave itidling to charge the battery. I never had problems with it. How is this any different? Doesn't the push-start just do the same thing as jumpstarting it?

Either way I'll have it all checked out for free at Pep Boys tomorrow.

Pitt

When you jumpstart a car, youre putting voltage to your battery then into the starter motor. Your battery will be low but will have been charged a bit by the jumpstart so when you start your car, it has enough voltage to supply your ecm (computer) and since the alternator kicks in when you start it keeps sufficient voltage going to your ecm so you wont encounter any problems. When you push start, you are using your transmission as the starter, therefore while the car is trying to start, your ecm voltage is probably below 11volts if not lower. And your alternator has to work super hard to charge your battery, sometimes this can burn an alternator. Not saying thats what happened to you. Since you say the car starts fine with the battery...are you sure its undercharging or maybe its overcharging? Think you would get a battery light if the alternator over charges too. Might of burned the regulator in the alternator and now its overcharging your battery(can be very bad for your electronics if thats the case). If you have a volt meter, I would measure the voltage at the battery while that battery light is on and see what you get...should be between 13.5-14.5 at the most. If anyone sees any of this information incorrect, please correct me

CobraStangGT16

I have a volt meter...I'll do that.

Thanks...I really hope I didn't burn it out...They're expensive as hell...[:@]

waggs

i'm guessing it's your alternator too. it happened in my escort when i had it. everything in your car is powered by your battery. your alternator just keeps charging your batt. while it's running. your batt prolly died cause the alt is not recharging the batt fast enough. only shur way to find out is to get it checked...