jmcraney

That "Auto" position on the control stem is sort of confusing. It has nothing to do with automatically turning the lights off after the ignition is turned off. The technology that automatically turns the lights off, after the ignition is turned off, works for all possible lights-on positions (park, on and auto). The Auto position on the stem is related to turning the headlights on and off in response to ambient light conditions while the ignition is on.

These "mysterious" battery discharges are almost certainly related to leaving the ignition on or a failure of the headlights AutoOff feature to complete because a door or trunk was not closed. The car has safeguards for all other situations such as leaving the Accessory power on or interior lights on.

In your experience, cited above, the reason that your charger would not charge the battery was probably because the parasitic load that discharged the battery was still on the battery and the dead battery plus the parasitic load was not supportable by your charger. The way to get around that is to disconnect one of the car's cables, to remove any parasitic loads, while you charge your battery. Restoring batteries to a full charge after they have been completely drained requires charging for about 24 hours when charged at a reasonable and safe rate.

The need to use two batteries for jumpstart is very characteristic of a completely discharged battery that has a parasitic load on it. Some things that you can do to help this is after you get the jumpers connected and before you try to start the car, check to make sure that the headlights are off and the ignition is off before you try to start the car. The best way to address this is to remove the battery and charge it or replace it with a fully charged battery. Remember that discharged batteries are not necessarily defective batteries and once they are recharged they may continue to provide satisfactory service for many years.

The "Mysterious Dead Batteries," "Wind Noise" and "TPMS Problems" seem to be areas that the Lexus dealerships have never developed a good understanding of.

We have discussed the AutoOff headlights and dead batteries in several threads. You may find some useful information in these threads:

https://www.clublexus.com/forums/ls4...s-problem.html

https://www.clublexus.com/forums/ls4...y-expires.html

https://www.clublexus.com/forums/ls4...ont-start.html

MarkGS

To the OP, I feel your pain. I have experienced the overnight drain 3 times in 3 months.

The first time was when my '12 LS was 1 week old. It was dead, dead, dead. No lights, except the red OEM security lights on the doors were still faintly blinking. Called Roadside Assistance and was back up and running in under 90 minutes. I chalked it up to a freak incident and took no further action.

Then I had a remote start installed. A couple of weeks later, drained battery again (overnight). This time I took it to the dealership, who slapped a band aid on the matter by replacing the battery.

Another month or so passed and had another drained battery incident. This time I noticed the rear tail lights were on (but no other lights), which seemed weird for a parked car. I took it back to the dealership where they questioned the after market remote start, then kept it over night to monitor any drain on the battery. Nothing was detected.

After explaining that I experienced the drain battery once before the remote start was installed, they requested I have the after market security system disconnected (remote start could stay connected). Of course, this made no sense since I had battery failure before the remote start/security system was added. But the dealership had to push the blame somewhere.

I have not made any changes.

I will read the other threads to see if I can glean any other information as I suspect this may not be the last time I experience the dead battery. I hope we both find some resolution soon.

jbrittmart

thanks to all the responders.

jmcraney was right once again.

last night when I got home I put the jump pack on just to see what it would do and sure enough it gave enough power to turn all the lights on and at least get the clicks when I tried to start it. I have since removed the battery and put it on a 2 amp charge which I will continue overnight. I checked the battery with the multimeter and got a reading of 12.12 which is certainly below 50% according to the scale posted previously.

I had noticed that my Auto Off light feature would choose not to work sometimes for seemingly no reason... I'd come out of a bar or restaurant and notice that my lights were still on. I'm guessing that this happened the other night and I just went inside the house and didn't notice that the lights were still on and they stayed on overnight. I don't get the Auto Off failure. I've had problems with it when all windows, doors and trunk were closed.... most times it works, sometimes it chooses not to... it's frustrating. I just didn't think leaving the lights on overnight would drain the battery completely.

Anyway, I'm thankful it's just the battery.

SBlexus

What jmcraney was right? The first post I post to you was check the battery wow!!!

jbrittmart

oh c'mon... I thanked everybody. lol

jmcraney was just more detailed and on the money.

you were correct as well...
better?

SBlexus

That's better, I know I'm a newbie but when it come down to cars I've been in the game a long time. I'm not crying about it, it's all good I stick to my quote. I'm glad your car is ok any you didn't have to blow a ton of money at the dealership.

G-SharK

According to my experience, the LS headlights will drain the car battery with an 1.5hrs. One night I parked my car in the garage and went inside to have dinner and wife came home 1.5hrs later and said my headlights were still on. I didn't think anything of it but to go and check why it was still on and turn it off. The next morning I was not able to start it up. By the way, this was a new battery that I just got replace a couple months ago. It was complete out of juice, so low that I could not disengaged my parking brakes. Had to go rent a battery jumper and it drained the jumper out too. Had to get another jumper and decided to use the jumper to disengaged the parking brakes and roll the car out of the garage so I can jump it using another car. Took the car in to Lexus and sure enough they said the battery was complete dead so they replaced it for free of charge.

So if you cannot start your car, its usually the battery.

Nospinzone

I don't have my manual handy to look this up, but I believe in my model year if you leave any electrical device on, it will automatically shut down after one hour to save the battery.

I know this works because about a year ago I had to wait several hours for my wife and it was most comfortable to wait in the car so I brought a movie to watch. I had the engine off and the "key" in Accessory mode. After one hour the DVD player and the Accessory function shut down. When I restarted it, the movie picked back up right where it had stopped.

The only thing I do not recall is if this only applies in Accessory mode.

FLYCT

Reviving an old thread.

I had the lights staying on issue when parked in the garage. I found the the switch on the driver door post was Intermitant. It seems the auto light circuit logic requires that for the lights OFF TIMER to start needs to sense door open and then close after ignition is shut off.

If the door switch does not activate properly then the lights stay on until the battery dies. You can confirm this for yourself. After pulling car into garage at night just sit in the car and don't open a door. Headlights stay on forever, or until your battery dies.

I also found that my front passenger switch was also Intermitant but not quite as bad. Dealer has ordered replacement switches. The service writer said she has seen this before in about 1 in 20 LS cars.

I would open the driver door and at times the light on the bottom edge of the door would not illuminate. If I touched the rubber boot that covers the door switch on the door post it would come on.

JR

jmcraney

Sir,

It would be normal operation for the lights to stay on, and completely discharge the battery, in the situation you described above.

I have covered this many times and I hope the moderators will not ask me to leave because some may sense that I am being argumentative. But, the way the exterior lights auto-off feature works is: the exterior lights are automatically extinguished after the Ignition is turned off, followed by a delay (the delay is customizable 0-30-60-90 seconds) which begins after at least one of the four doors or trunk is opened followed by none of the doors or trunk open - in other words the delay starts after the last door or trunk is closed and the lights will not automatically turn off if the car senses that one of the doors or trunk is open.

The phantom battery discharges that some are experiencing with these cars is mainly related to a failure of the auto-door-close feature to complete.

FLYCT

We agree.

I just wanted to add that perhaps one root cause of the phantom battery discharge may be an Intermitant door OPEN/CLOSE switch on the door post. This would cause, as you correctly state, "the failure of the auto-door-close feature to complete.

Both the driver and passenger switches on my LS have been confirmed as being Intermitant..

What led me to this was, one evening with the driver door open in my garage, the lower curtesy light at the bottom of the door was flickering like morse code. At other times it would not even turn on. If I twiddled the rubber boot that covers the switch plunger I would be able to make the light stay on with the door open.

JR