Pusha100

So My battery in my 2003 Lexus GS430, keeps on dying over night and I found that my NO# 39 (ALT-S) fuse is blown.

I looked in the manual and it says "charging system"

If someone can kindly let me know what this fuse controls and if this is the reason why my battery is dying overnight?

PS: Also I had my battery & alternator both tested and they are good

Thanks

AMSMIKE

iTrader: (40)

something is draining the battery or a bad battery. are you sure your battery is good?

anything aftermarket wired in the car? alarm? stereo?

did you do anything to the car? then it happened? or did this just randomly start happening?

Pusha100

Hey, thanks for the help!!

Yes the alternator is good & the battery is good (had them both tested)

And I have an aftermarket radio in the car, could this be the reason?

And yes it randomly started happening

xplosion79

That fuse is for the alternator and the reason its dying is because when the fuse is blown, the alternator is not charging the battery. Maybe a bad voltage regulator in the alternator?