2000 Mustang v-6, Battery Light wants to flicker on, stays on for a while, then goes off,then back on and flickers. Had alternator out 2 times now and tested ok, put volt meter across battery terminals reading about 2.5 volts higher when running, checked both terminal, 2 ground wires on the front of motor compartment off of neg. terminal ,still have flicker, any help anyone else have this problem. Thanks for Help

 

2.5 volts isn't enuff, replace the battery. Car battery's are a little over 12 volts, almost 13 if I remember correctly.

 

he said 2.5 volts higher when running, not only 2.5 volts, need to know what voltage before/after

 

The voltage is a little over 12 volt when motor is off with motor running I am getting like 14.7 volts. Never woke up to a dead battery and we did replace the original battery to see if that helped but still have the flicker. Thanks

 

Check all of your connections, and clean any corrossion.

 

I had the same problem and it was my alternator. Wait until it's dark and turn your lights on up against the garage. Rev the engine and see if the lights dim, that is a sure way to tell. It may charge fine at idle, but when you get on it, it could go bad.

 

Oops, I misread the higher, clean the terminals first, and have your alt tested, they're easy to take out.

 

So do you think even after I had it test at advance off the car it could still be a bad alternator, they spun it on there machine and checked it, and I been cleaning up any corrosion I find even loosened up ground wires and wire brushed them and retighten.Thanks Again

 

I had Autozone and Advanced Auto test my alternator. Both told me my problem was my battery. It was old anyway so I replaced it. Did the exact same thing. My problem was my alternator.

 

Did they test your alternator and tell you that it was good, we replaced battery already just because it was the original from new , and had the alternator out and had them check it and they said it was good, I might just tear it off and try another, there kind of expensive $153 at advance for a remanufacture, any one get any better prices. Thanks