1996 Lexus ES 300 Battery Drain

Tiny
ALICE2009
  • MEMBER
  • 1996 LEXUS ES 300
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 117,000 MILES
Dear Mechanics,
My Lexas ES300 is draining the battery. My mechanic detected a 20mA of electric power flow, but could not find out why and he told me the alternator looks ok. I have changed 4 brand new batteries in the last 6 weeks. One of it even could not be recharged. Start from last week, I disconnect the positive end of the fully charged battery whenever I do not use the car. It should avoid all the possible power drain. Now, again the car will not start. It looks like an alternator problem, but the symptom is kind of wired. What happened is after I connected the battery, all the door lights were very bright, after I started the car, the panel flashed once, and turn dark immediately. All lights were gone. The car appears totally dead now. If the power is less than 12V, the lights are just dimmer. I suspect something wrong with the electric circuit and short the power line somewhere. Two years ago, I forgot to close my sunroof, rain flooded the car from inside. I did not notice it and start the car. I can hear very loud like explosion sound coming from the sound system inside the door. However, the car runs fine for two years. If the circuit gone bad now, will it short the battery(one of the new battery could not be recharged)? Do you think it is the electric circuit problem or the alternator problem. I really appreciate your comments.
Sincerely,
Alice
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Tuesday, November 24th, 2009 AT 10:48 AM

5 Replies

Tiny
MERLIN2021
  • EXPERT
First, whenever you remove a battery cable to stop power flow, it is the negative cable that is to be removed...now if the alternator has a bad diode inside on the diode trio, it can cause an electrical draw. Test this way,
http://www.2carpros.com/first_things/why_is_my_car_battery_dead_over_night.htm
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Tuesday, November 24th, 2009 AT 11:20 AM
Tiny
ALICE2009
  • MEMBER
I do not know I should disconnect the negative cable. Thank you for pointing that out!
I just read the page for alternator testing
http://www.2carpros.com/how_to/how_to_test_alternator.htm
and I remember the mechanics did this check and my alternator yields 14.1voltes. He also performed step 4, maybe too long and burnt it?
If I replace the alternator, but the circuit is bad, will it burn the new alternator and battery?
Thanks again!
-Alice
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Tuesday, November 24th, 2009 AT 12:41 PM
Tiny
MERLIN2021
  • EXPERT
Get an analog voltmeter remove the negative battery cable, attach the Black lead to the battery post, Red lead to cable end, then pull fuses one at a time, make sure there are no accessories or lights in the on position, Key off! Close the door after each fuse and check meter, when you pull the fuse for the bad curcuit, the meter will drop to 1 volt or so. Check all fuses, even under the hood. If meter does not drop, remove the battery connection from the alternator, if it drops now, the diodes are bad in the alternator. Put the fuse back in were it goes as you go so you don't forget which fuse goes were!
http://www.2carpros.com/first_things/why_is_my_car_battery_dead_over_night.htm
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Tuesday, November 24th, 2009 AT 2:17 PM
Tiny
ALICE2009
  • MEMBER
Hi merlin2021, thank you for your reply. I hope I live in Boston and I can bring the car to you, but I live in Philadelphia. My previous technicians performed those tests you mentioned(At least I remember he pulled out the fuses one by one), but did not find anything wrong. Do you happen to know where I can find a good certified master technician in my area? Thanks!
-Alice
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Wednesday, November 25th, 2009 AT 11:11 AM
Tiny
MERLIN2021
  • EXPERT
Sorry, Don't know anyone in Philly!
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Wednesday, November 25th, 2009 AT 12:51 PM

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