Jason B

Callisto1

I changed out the battery on my 2010 GL without any problem, but with a BIG CAVEAT.
There is a Sears Auto with a drive thru battery lane about 2 miles from my house, which has always been the quickest and cheapest way to change a dying battery. But they refused to change my 2010 GL battery because they had previously screwed up GL & ML battery changes, requiring towing to the dealer and $1000 repair charge. They are no longer allowed to change GL and ML batteries. So apparently there is some risk to DIY if you are not careful.
Here is the youtube video guide that I followed. Not the slickest production, but thorough and includes a list of tools.
I was careful to tape off each lead as I disconnected it so there was no chance of a short.
The only thing I would add is to connect another battery to your your jumper cable posts before you disconnect the dying battery. That seems to preserve some settings in case the aux battery is weak as well.
I expect more experienced members will chime in to correct or clarify these comments, but it worked for me.

And FWIW when it's this much of a hassle to change the battery, I believe in buying a quality battery, not the cheapest available.

chsu74

I had my tender plugged in so no memory would be lost. Be careful of your ratchet handle is all metal. I would tape up the handle end so you dont accidentally hit a negative terminal when unbolting the positive.

Yes move your pass seat up and forward as much as you can. Plenty of good instructions on youtube and replace the aux battery at the same time. OEM backup battery was like $40. Duracell from batteries plus replacement was $15-20.

DennisG01

I was at my indy dealer when he replaced my battery. I was going to take it home to do it, but he did it for free. He removed the seat rather than struggling with sliding it in under the seat. It took all of about 3-5 minutes to remove the seat. I was surprised it was so easy to remove the seat - certainly seems like time well spent when it makes the actual job much easier and safer (much less chance of shorting something).

Jason B

DennisG01

So either something is obstructing it from the underside/around the edge, or the latching mechanism is worn/broken. You'll have to look closer to figure it out. I'd help, but it's hard to do that from here in PA!

Jason B

That's funny. I'm in Harrisburg!

DennisG01

Small world!

FYI, just keep on top of the battery issue. If the car is used on a regular (even a somewhat regular) basis, it shouldn't need to be charged. A healthy battery should start your engine even after sitting for 2 weeks. I've had no issues starting my engine (which takes more juice to start it since it's a diesel) after sitting for even longer than that. If you continue to have a problem, there's either an excessive draw on it somewhere or the battery is, indeed, on it's last legs. For good measure, what's the voltage reading at the battery when the engine is running? 14-ish is about right.

Callisto1

If the battery is 6 years old, just replace it now and save yourself the headache of when it dies without warning at the most inconvenient time. My GL battery died in Everglades Nat'l Park with no cell service when the battery was 3 years old. Got the park ranger to help and we jump started it from his golf cart batteries. At 3 years old, my 1998 E320 wagon battery died as I was leaving my office to take an important client to lunch. No prior warning no nothing, but the battery was so dead it wouldn't even open the door locks. Dealer sent a service vehicle with new battery and the service tech said that was par for the course. 3 to 4 years. So 6 years is extended life support. I replaced my E320 battery every 4 years after that, and in 2013 sold the car to my oldest friend who is still driving it in Maine today with no other problems besides replacing the cheap plastic gears in the power windows. And cloudy headlight covers of course. Wish I could say the same about reliability on the GL350...

IvanP

HI Jason,
How do you like your GL? I just picked up a 2012 GL550 for my wife. Will you be adding some MidCity Engineering toys to this car as you did to your S550? I am thinking about adding the remote starter to this one as well. I love it on the S550 I have, especially in the summer.
Cheers,
Ivan

Jason B

Yes, it is a small world. We should meet up sometime when you're around here. Right now it only gets driven 2-3 times per week, and recently with these cold temps, my garage has been about 36 degrees inside. It's been doing well the past few days and seems to be holding charge well.

Love it. The S550 is the king though, but for SUV's I think this is... I've done a lot of unique things to this truck. It was black exterior, and is now Satin Peal White, wrapped it, with black leather interior and new wheels. It's looks great and get tons of compliments everywhere I go, from young to old.

Funny, I'm a dealer for MidCIty which makes a remote start that works with the factory Mercedes key. Very cool, works for all Mercedes makes and models and is a must since you don't need a NEW KEY. I need to add pics in here for your guys to see this thing. I was out the other day and a guy came up to me and said, "hey, what year is that? 2020?" ha,. It looks great with this wrap.

Jason B

IvanP

Very nice, Jason! The wheels are awesome. I need to get my wheels redone on the GL, got the car with some curb rash. The car has chromed 21" AMG rims and the chrome is peeling in couple of spots. I am not big fan of chrome wheels, but wife likes it. Well, it is her car so I will probably stay with the chromed look for now, just have it refinished in PVD chrome, rather than re-plating the old way.
Cheers,
Ivan

Jason B

IvanP

PVD = Particle Vapor Deposition - different technique than traditional plating.

Jason B

Ok, well, battery died again. So, it seems this is the same battery that the w221 S class takes. I got one in that a year ago from Sam's. 3 year free replacement and it's $169 installed. Dealer wants $485 isntalled

Going to do it later this week and have them do it.

http://www.samsclub.com/sams/auto-gr...uestid=4375412
$169


Specifications
20 amp hour rate:92
Battery Electrolyte Composition:Glass Mat
Battery End Type:Top Post
Battery Purpose:Starting Lighting Instrumentation
BCI Group Size:49
CA at 32 degrees F:975
CCA at 0 degrees F:850
DIN code:H8/L5
Freight Class:65
Polarity:Right Positive
Reserve Capacity:170
Terminal TypeIN
Volts:12

GLguy

Does GL require AGM battery? Could not remember which one it takes.

Jason B

Keyser Soze

Replaced battery in 2007 Ml a few years ago. Other than wrestling the old battery up the tight opening, didn't seem to difficult. Yesterday, changed the battery in my 2010 GL. Scoffed at your description of removing the seat......Wished I had heeded your advice. It took the two of us 4 hours, scuffed fingers, and sore muscles from standing on our heads to get the battery out, but then replacing the aux battery which I remembered as an easy switch on the ML, was an ordeal on the GL. Removing the seat would have saved 3 hours and a lot of aches and pains.
Did not bother with keeping the circuit alive. Though both batteries were out for 3 hours, it took all of five minutes sitting in the driver's seat to reset the 6 windows and sun roof auto open and close features. The only memory lost was the radio presets (big deal) and probably the transmission education, another no big deal..........It's far preferred to taking a chance with sparks and shorts and possible damage to the computers......

Jason B

So the question is, what size socket needed to remove seat? Maybe I'll tell them to do that?

And on the secondary battery for the GL, you're saying that's not easy to do? I've seen it in the rear panel I think before when I tool panel off before.

EDIT, ok didn't realize the aux battery was diff for you 2010. Here is where all batteries are for 2012:

Keyser Soze

The 2010 Gl's aux battery sits beside the main battery. I expect it's the same for MLs and GLs through 2011..........Don't know socket size for seat, 10 or 13mm are favorites with Mercedes.........

DennisG01

I've been caught in similar situations, myself. Doing it a certain way 'cause I'm convinced the other way - "assumed" to be the harder way - would take longer. And then after I'm done... shoot - should of done it the "harder" way

Should be easy enough to figure out what socket/wrench to use by putting a wrench on the bolts? On the other hand, if I had to figure out what size tool to use for the place that is doing the work for me... I think I would find a new place! But, I think the bolt heads are those external torx head? I'm not positive - take a look under the seat to check. If I'm remembering correctly, though, I think I've used a 6-point wrench on male torx in the past? Probably doesn't fit perfect, but as long as the bolt is rusted up...

The battery does not lie on it's side - at least not in my model year... or are you referring to the aux battery? Haven't replaced that one yet and don't recall well enough from when my Indy did the main battery. From the picture/graphic you posted, it looks like the battery is standing normally as well.

Jason B