2000 Lexus RX 300 battery drain

Tiny
KENTHUGGINS
  • MEMBER
  • 2000 LEXUS RX 300
Electrical problem
2000 Lexus RX 300 94000 miles

battery has slow drain that will drop it to a no start condition in 4 days if it just sits that long.
mechanic ran tests and could not find.
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Sunday, June 7th, 2009 AT 9:02 PM

3 Replies

Tiny
ZACKMAN
  • MEMBER
Electrical drain is one of the most dreaded problems a technician want to look into. I am sure that he has done all these but, just so that we cover all the basic.

1. How old is the battery? If it is more than 3 years old, fully charge the battery and have an auto parts store such as Checker O'Reilly test it using their battery tester. The tester is more accurate than a basic voltmeter. If the battery is low (right after it was charged), you may want to consider replacing the battery.
2. Check and make sure that both battery terminals are free of corrosion and have tight connection.
3. Once 1 and 2 completed, attach a digital voltmeter probes to the battery. With the key off the ignition, turn off all lights and close all doors. Record the voltage. You have to pull one fuse at a time. Record what fuse was pulled and the voltage with the fuse pulled out. Re-insert the fuse. Do this until all fuses are tested. For every voltage fluctuation when a fuse is pulled, you know there is a power drain. Now you need to concentrate on what circuit the said fuse is controlling to locate your power drain.
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Monday, June 8th, 2009 AT 1:00 AM
Tiny
KENTHUGGINS
  • MEMBER
Battery is new and mechanic did all that you stated and could not isolate any fuse as the circuit with the problem. Now what?
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Monday, June 8th, 2009 AT 12:36 PM
Tiny
RASMATAZ
  • MEMBER
To add on to Mr. Jack here's the ammeter way for a battery drain test


http://www.2carpros.com/forum/automotive_pictures/12900_parastic_draw_1_101.jpg

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Monday, June 8th, 2009 AT 6:09 PM

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