Kate0506

So I've had my 2010 GL450 for about 3 months now... and have loved every second of that 3 months. Just Yesterday, A family member was hospitalized. I got a call and ATTEMPTED to rush over to the hospital. Hop in my GL and hit the Engine Start button and...nothing. Everything on the car was really dim, and it wouldn't turn over. I took the button out, and put the key in and still nothing. This was the 3rd time in a month that this has happened. I hadn't thought anything of it (We just charge it at home) until this became a reoccuring problem. The worst thing was that I had JUST gotten my new car the day before (2 days ago today), and had to take it. New Bentley + Hospital Parking Lot =
It was all perfect and detailed. Anyway... My husband charged the battery last night, and it's been charged so far today... Let's see what tomorrow holds for us. I don't know if this has been a problem with anyone else's GL, certainly not this early in ownership? Help!?

43221B

You need to take it to the dealership and get the problem diagnosed. It could be a simple fix. My battery drained on my 09 overnight and it required a 15 min diagnostic and repair event at the dealership while I waited. 10,000 miles later and no problems. If you aren't driving it for more than a week at a time, you need to purchase a trickle charger.

Fourdiesel

Certainly there have been battery drain issues on Gls of various years. The electrical system is EXTREMELY complex and is 'computer' controlled. If a computer is slightly mis-programmed or a logic sequence is out of whack - bingo - a battery drain occurs. Search this forum and you will see many examples of 'SAM' caused battery drains, etc. This is NOT something that should happen AT ALL with Mercedes, but it does!

rctoon

Where is the battery located in the 2010 GL 450?

reddog

On my 2007 GL450 the battery is located under the front passenger seat. There are charging terminals under the hood on the right side. Look in the owners' manual under "jump-starting".

Fourdiesel

As far as I know, the battery on ALL GLs, all years, is under the front passenger seat (aux battery also).

Popo

Aux battery? I have not looked under the seat, but i was not aware there was more than 1 battery in the car.

What is the Aux battery for?

fs1013

I need to garage our GL350 for a couple month. So where do I connect the battery charger? Terminals under the hood or under the front passenger seat?

slim nicky

I once left my fog lights on overnight and it drained battery (did not realize they would not get turned off automatically).... you sure everything was off?

reddog

Terminals under the hood.

Fourdiesel

The Auxiliary battery is kind of like a emergency back up power supply so that when, for example, the main battery is changed out all power isn't lost to essential systems. The computer is one of those essential systems and the computer also controls the charging of each battery and sheds loads automatically if a fault in one of the batteries is detected.

fs1013

Thanks a lot reddog!

Right before your response, the service advisor actually told me to coonnect it to the AUX battery. I looked at the place and it's hard to get to.

fivestarman3308

So, aside from going to the MB dealership, where can I buy the best battery for a GL 450?

Fourdiesel

I'd start with Johnson Controls online, see if I could get a part number match up and perhaps a list of dealers near me where the battery might be ordered through. Or maybe find a dealer through the web and let them find the part number for your rig. See attachment for more (dated) information.

MBtech1098

WRONG...The aux battery serves one purpose, and one purpose only.

Due to there being no mechanical connection between the shifter (Direct Select lever) and the transmission gear selector (ISM), there was a need to be able to engage PARK in the event of a battery failure. There is a microswitch in the ignition switch (EIS) that if, and when the key is removed in a vehicle with a dead battery, the aux battery will supply enough power to allow the servo to engage park.

Aside from that, to the OP, it definitely sounds like you have a quiescent (key-off) type of current draw. Many things can cause it, also AGM (glass-mat) batteries can not sustain voltages below 9-10 volts, as this will kill the battery. So additionally you may need a battery.

Fourdiesel

So, if I understand correctly, my car, which has keyless go (and the key is never removed) can do without the aux battery just fine since, even with a dead battery, the park will engage anyway?

alx

If you have opened your rear lid with the key fob or your rear lid is misaligned and does not latch properly- your battery has drained. There is a tsb for that and the rear CAM software module needs to be reflashed.

MBtech1098

Your question is slightly unclear. I forgot to mention about KG...if you shut off the engine and open the door, park will engage. If the battery is dead, and you have no aux battery, park will not engage.

MBtech1098

I believe you are reffering to the rear SAM, not CAM. Also that DTB does not apply to 2010 model year.

oxotnik

I have 2010 GL350 BT and have kind of similar problem too. Sometimes (mostly when in cooler temperatures) it will not start... you put the key in turn.. it does click and sounds like there is no juice... Messege says REMOVE KEY... I remove key... do it several times then it starts. Took a car to the dealership... they kept it for a day... I started OK all the time... And I still have this problem....

alx

err. SAM- yes.

did not know about 2010... about time that dtb becomes n/a

alex

Fourdiesel

Ok, I think I understand now. If I forget to press the 'Park' button after I stop; then open the door (in the case of keyless go), or remove the key for all other cars; the car will go into park 'automatically'. The aux battery is there to put the Park pawl in place in the event the main battery is dead.
If that is the ONLY reason for the aux battery, then there must be some extremely obscure safety rule somewhere about 'fail safe' into park mode that would warrant the expense of providing and maintaining this extra battery. I realize that the so called 'parking' brake requires a great deal of pressure to hold the car on a grade, but depending on the park pawl is also risky.

MBtech1098

EXACTLY...this battery is very small. I tried to find a pic of it, but was unable to, I'm out of work next week, but when I get back I'll snap a pic of one. Every MB that has an ISM (no direct link from shifter to trans) has one of these batteries(US market: 164, 251, 212, & some 221 without dual battery), EXCEPT the SLS...but the trans in that is a different animal all together.

Fourdiesel

Is this the pic you are looking for? The smaller battery at the lower right.

MBtech1098

Yup that's it.