1999 lexus es 300 I replaced alternator and battery -- batterry drains totally flat if left for 10 days or so -- nothing left on ( lights and etc

look at the ground and pos. line at battery, look at stater wire off alternator , it tells the alternator pos+ or Neg- ground. corrosion of wire ends can cause this.

You have a wire grounding somwhere, Look for any cut wires or frayed wires,

Hi Susie, Turn on the head lights and get someone to observe them while trying to start. If they dim during trying to start, replace the battery. Regards John

Hi there Amy:
Check this for 1999 Lexus ES 300 3.0 liter DOHC V-6 (1MZ-FE) firing order



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Have the battery load tested. This is likely a short in the battery itself and not in the car. You will have a small amount of draw in a computer controlled vehicle. This is very normal for the "keep alive". Older cars with no computer will have no draw. Let me know.

alternators come in different amperage rating. connect a good ammeter in series with battery positive terminal after engine is at idle. or connect a voltmeter on your battery. with engine at idle, turn on lights and a/c, raise idle at between 1500 to 1800 rpm. voltage reading should be 13-14 volts. if not, alternator is too small. check the amperage rating of your original alternator. good luck

Hey, Take your care to an good battery shop, have then check the alternator output.. sound like there is an issue of charging ... or there is a major drain on the battery.. either way, they will be able to help you.

when your car is running disconnect the positive cord from the battery. if the car stays on, than it is your alternator, if not its your battery. also if the car stays on, the head lights go dim if the alternator is malfunctioning

Unscrew the gas cap, wait 30 sec and screw it back on making 3 clicks/cracks. Should be ok in a day or two.

It could be a problem with the starter motor.