sloman

i have a v6 2003 mustang. about 8 months ago my car would randombly lose power and eventually would not start at all. i replaced the alternator and it fixed the issue and did not have another problem for about 6 months. now in the past 2 months i have replaced the alternator 3 times and each time it is lasting a little over 2 weeks. i am being told that something must be draining the battery when the engine is on which is making the alternator over exurt itself and killing it. what should i be replacing now to get it to work. i was thinking about replacing the positive and negative cables because i was told that the ground can do this. also my headlights do not work which has been that way for about 4 months now. i have been using the high beams instead. the headlight went out simultaneously one night. is there any chance maybe they are draining the battery. please give me any insight you can into the issue. thanks in advance.

95SHO

Have you checkes voltage when the car is running? Where are you getting your alternators because depending on where you are buying them they could be poorly rebuilt. Aslo load test the battery, a bad battery can kill an alternator. I would go get a new alternator and battery and go from there.

As for the lights have you tried replacing them lol.

Derf00

Maybe you have an electrical short in the headlight harness or headlight switch in the column.

Are these factory headlights or aftermarket?

sloman

the lights are factory lights. i have gotten the 4 alternators all from auto salvage areas. i take the battery to either discount or advanced and they tell me that it is fine but it always takes so long to get a charge on it for them to even read it. im going to try replacing the terminals again and then the wiring harness for my lights as well.

Chucks95RT

All of the help you're going to get here is based on a stock electrical ssytem. If you have extra load drawing items like DVD/Head Unit/SUBS...I would start there first...

I would think an electrical SYSTEM test is going to be your best bet.

I don't know if our cars have different voltage ranges on batteries, but engine off...12.6V is minimum. At idle it should jump from 13.6-14.6 v (I will edit if this is incorrect....)

Have them check the battery IN the car. Have them check the voltage with engine off, at idle and at idle with accessories on.

Test the output of the alternator with the battery installed, and with the battery disconnected.

The starter is part of the electrical system...the grounds on there are important as well.

I'm thinking you have a load draw somewhere...corroded wires have alot more resistance than clean ones...resistance is bad in a charging system.

Update us when it is figured out, so the thread is completed with an answer for future peoples

Daehawk

Had a problem like this. Had the battery and alt both checked. Both tested fine. But the battery kept draining
. So took it to a alternator guy who had been rebuilding them for 60 years. He found it had 2 bad diodes and replaced all of them and new brushes and such with better parts / more juice and for like $75 and 30 min.

Jump ahead and after a while my battery never seems to charge good. Turns out the bad alt had killed the battery. So I buy a top line battery and everything is good.

Months go by and the drain starts again. So now I had both a new battery and a new alt and it's doing it again. I can't find the drain anywhere so i solve my problem by buying a boost pack. You charge it up and keep in the trunk. I'd have to boost off to go somewhere. If Iwent anywhere again within 3 days I was good. it would start. Then that starting going down..2 days it was dead. 1 day and it was dead. Then it would need a boost if i went in a store.

Went back and found the battery had a bad cell. Got yet another battery...free mind you...and since then no problem.

So I'd 1. go to a real alternator guy that knows his stuff...and 2. get a good battery no matter what they tell you.

EDIT: And make sure that alternator is grounded good.

Chucks95RT

Any dead shorts, would not only drain the battery but most likely melt the wiring. Low voltage, high current battery = toasty wires.

Like I said previously, start with checking the entire system and check grounds...from there buy what you need. Randomly replacing parts gets expensive.