i have a 2002 is300 here's my problem i was driving my car and lih
ghts started popping up on the dash battery ,trac off, check eng,brake and srs i noticed my battery volts were dropping i turned on my headlights and my tv turned off parked car and didnt want to start so i changed the alternator everything was fine for about an hour then the battery light started blinking on and off and noticed the volts were dropping again so i went to autozone and the cars battery starter and alternator were checked they said the volt regulator failed ..some one told me i had a loose ground but i checked the ground from the battery to the motor and it seemed fine was wondering if it could be my alternator plug some one please help me out thank you

 

check volts to the alternator pigtail, and i know this sounds weird but have you changed your drive belt? I had a car one time I was diagnosing and the belt was loose and stretched and the alternator wasnt spinning fast enough weird but cars are strange.

 

perhaps the new/reman alternator was defective?

out of all aftermarket (and even new OE parts), alternators have the highest DOA percentage...

 

I agree with mitsuguy, reman alternators suck and 9 times out of ten they r boxed defective. let us know what you have found

 

Good lookn found the problem the positive cable from the alternator that goes to the fuse box was loose and was giving me a bad connection so the volt regulator was not turning on and charging my battery ..