So as my title says, been driving my 03 LS for two years now, timing belt done last year, zero issues otherwise. Last week at work came out to head home and the battery was flat, no biggie I thought got a boost and drove it home. Fired up okay the next morning and ran fine the next few days.
Flew out to Phoenix last Saturday and got in yesterday to a flat battery again, cranked the key and the usual click, click, click. I thought forget it at this point lets install a new battery, winter is coming. So I grabbed a new battery of the shelf, had the parts guys test it, brought it home and gave it a top up charge.
Checked the voltage and it was a steady 12.6, cranked the key and nothing. All the accessories work, headlights, stereo, windows, signals, so I know the clamps are good. Thought what the heck I'll boost it with the wife's highlander, still will not crank, no click, click ,click nothing, but everything else works.

I have had zero faulty starter symptoms, and have checked the starter fuse, and the others right next to the battery. It almost seems like its immobilized, but I have tried all three keys and nothing, put the old charged battery back in and still nothing. If any of you could throw a few more ideas my way before getting it towed to my mechanic, I would appreciate it thanks.

A faulty alternator can cause engine start issues, which could also be the underlying cause of the battery problem. Unfortunately, you can't test the alternator output when the engine doesn't run. It does sound like a fuse has blown, which may be caused by a short in the alternator.

I'd like to know the outcome, because I may replace my battery proactively...it has a sticker that it was installed in early '12, and it seems straightforward like my Maxima (unlike the BMW which has all kinds of stuff attached to the battery such as a IBS and requires registration whenever the battery is swapped).

Our cars do not need programming when a battery is replaced, right (to tell the car what it got and that it's been replaced)?

registration?....just cause you put in a new battery? no, no need for that.
you lose some settings but not a big deal

yep, for example if the oem is 90 Ah / 720 CCA lead acid, and you replace it with the same, the car needs to be told through registration. If not, it thinks the battery is 4-5-6 yo and won't fully charge it. If you change the capacity or to agm, now the car needs to be coded. I have software to register, but not to code...

i suppose since our LSs are so easy to replace, maybe I should just continue to use what's in it. I have a spare 3 1/2 y.o. 24F from the Maxima as well.....

This is false. I replaced my battery and did nothing else and it worked fine.

For some models battery replacement in Mercedes and BMW universe can be pretty complicated. There are stories on the forums of some recent model MBs being completely bricked because battery was swapped without following precisely and in exact order steps in service manual required to disconnect, install and reconnect. I not talking about making any actual errors like swapping cables or shorting battery with a tool, etc.


Replacing battery on the LS430 is very simple. Disconnect cables, negative first then positive, install battery and reconnect cables, positive first than negative. Done

. There's an entire section on BMW software such as Rheingold (what the dealers use). Using the same capacity is considered diagnostics. But changing to a different capacity, or from lead acid to AGM is coding/programming. When coding, there is supposed to be a clean power source connected to the car. A coworker told me always back up your car before coding it (BMW). This way you can always restore it to what it was before. I found that concept to be funny.

Edit: cool. Nothing else to do with the LS....I'd likely get an Interstate 24F from Costco....

I also just replaced my battery in my 8 month old Outback 3.6 with the Interstate line from Costco. The OEM had not failed but I did not trust it. One of the fails from Subaru was using a rather crappy battery from the factory with low reserve & only 490 CCA. For $82.99 I got a group 34 & 800 CCA's. It is hard to beat that price. Consumer Reports rates the Interstate line good. The Diehard Platinum line has consistently topped battery ratings but the price is almost triple vs the Costco Interstate battery.

Sorry to go off topic here but any itch to get another LS?

. If I'm not mistaken, Subarus still have batteries which have filler caps...talk about a throwback! . I looked yesterday....Costco has a 3 1/2 yr / 42 mo replacement warranty....

Thanks for all the suggestion guys, finally got it towed to the mechanic, after trying every thing I could. He says it's a broken wire, unfortunately it was behind/under the intake, which they had to remove. I'll find out more when I pick it up next week, a few hundred bucks for labor no doubt. I would have almost preferred it to be the starter, seeing as if that ever fails it's the same procedure over again, and one less thing to worry about down the road, but such is life.