Three Dead Batteries in a Year

Hmmmm, maybe the dealer has Lexus technical information that would solve this problem.

At this point, NOTHING should be out of the question--especially the dealer. It would be worth it to find a good dealership service department and pay them some amount of money to try to diagnose this.

do they put volt meter in lexus ? if they do then it is easy to see but i agree that it is likely faulty charging system and japanese is a bit weak on this.

First you may want to disconnect the battery for those few weeks and see if it'll start the car after you reconnect it, I bet it will.

Next get Radio Shack 63 ma fuse, or lopwer if you can find one. You could put that in series with the battery while the car sits for weeks and and see if it blows. You could check it every day.

If its not the battery or the charging system then you have a gremlin. One way to isolate it is by taking out half the fuses and letting the car sit. If the battery is dead, then you've found the good half of the fuses. Now put all the fuses back in and next time remove half of th half you previously removed and by doing this you'll isolate the circuit. After the circuit is isolated you have a much better chance of finding the culprit. It'll take some time but be cheaper than buying new batteries or relying on the dummies at you garage.

I danced this same dance w/my 96 LS400. The problem turned out to be a defective alternator. First took it up to local Autozone store. They checked battery & alternator, couldn't find anything wrong. Finally took it to Lex dealership. They ran all sorts of load tests showing battery was fine and alternator was fine with the car running. They said they weren't

did you ever help jumpstarted another car with yours running ? this can lead to all sort of intermittent problems down the road.

Solid trouble shooting advice. Had a similar problem (not on a Lexus) that was traced to a bad electric seat switch. Good luck.