jangjong

Hi Guys, New to the forum..

My dad has 2009 ML350.

Last week, this indicator showed up



My dad used to be a mechanic, and he thought it was the alternator that was failing.. so he replaced the alternator and the indicator was gone. this was Friday.

and today (monday), the light is back on. i guess it wasn't the alternator after all

he said he bought this battery checker (i guess to check the voltage) and the battery shows correct voltage.

now from my research, i learned there are two batteries, main and second.

is it true that it will show a RED indicator if it was the main battery failing and a WHITE indicator if it was the second battery?

if so, do you think it means it's the problem with second battery? and do you think it would be safe enough to drive at least until this weekend?

thanks in advance

Borko

The white indicator shows the second (smaller) battery is going bad. Which one of the two batteries did your dad check.
I believe that you won't have any problem driving it until this weekend.
This might help a bit
https://mbworld.org/forums/m-class-w...-location.html
http://www.benzworld.org/forums/w164...y-removal.html

jangjong

he checked the main one. he wasn't aware of the 2nd battery until i showed him some pictures online.

do you know where i can get the 2nd battery in the U.S.?

sheepdog8

I think the MB small battery is about $80, or $40 if you buy aftermarket. Not hard to change, just a time consuming pain. Do not unhook the large & small batteries at the same time.

jangjong

yea i've been doing a lot of research and found that out too lol

do you know where i can get the aftermarket battery?

and also, do dealers usually have these in stock?

Keyser Soze

I got mine at 'Batteries Plus'........Perfect fit.........About $20.
WKA12-1.3F 12V 1.3Ah Werker Battery with F1 Terminal 2006 V6 3.5L 850CCA Auxiliary ML350 Mercedes Benz Car and Truck
2006 V6 3.5L 850CCA Auxiliary ML350 Mercedes Benz Car and Truck 12V.

sheepdog8

Awesome

jangjong

sweeeeeeeeeeet
thanks a lot guys.

jangjong

Just wanted to update on this in case someone is in my situation with 2009 ML350

Few days ago.. I called a dealership around me and asked them if they have the second battery in stock.. and this guy "insisted" that 2009 ML350 only has one battery.
so i couldnt even ask them how much they were

and yesterday, I went to help my dad with this, and he already started on it. He already had the main battery out. This is what it looked like after the main battery is removed.



In case people want to know where this aux battery is, I marked it on the picture.
so.. obviously the guy at the dealership was wrong. what a fool.

Here are some close up shot of the aux battery:






You can get a replacement battery in the US at BatteriesPlus store. This is the exact battery you can get for 2009 ML 350. It was like $25 i think.

http://www.batteriesplus.com/product...-Terminal.aspx

One thing you don't want to do though, is asking them for aux batteries for 2009 ML 350.. They have that in the system but it looks like they have a wrong one for 2009.

I forgot to take a picture of the old battery or the new battery.. but the old battery specifies that it's 12V 1.2AH.. This one is 12V 1.3AH. just wanted to mention that here.. also this one from batteries plus is smaller than the original, but it's slightly small which doesnt really matter too much actually.

To remove this aux battery, my dad and I had such a hard time.. so I wanted to show you what you have to do to remove them.

First you have to untighten this nut first.. sorry I forget which size it is :/ but took us like 5 mins to actually find this guy



And then when you remove the nut, you have to slide the cover for the batteries to the direction that's shown on the picture to remove the cover.. (i didnt do it.. my dad told me that's how he removed it.. maybe someone can correct me if im wrong)



and that's how i removed the aux battery.

I know it was in the link that Borko posted here.. but just wanted to show you actual pics heh..

And.. thanks to sheepdog, i didn't unhook both of them at the same time.. always had one or the other plugged in.. and didnt lose any setting!

perfect!

and i tested the aux battery that we took out. .and it was showing lower voltage than 12V.. so this was the problem (fingers crossed)


anyway, thanks again for answers guys!

cburda

Thanks...
Great info and picks.
So there is no way to tell which battery is going bad based on dash info...
And you didn't need the radio reset code since you always kept one battery connected?...

Thanks Again

jangjong

Well, according to Borko

However, I really haven't seen any red or other indicators on that dash so it's hard to tell if it really is gonna show me the sign in red.

I've seen the red battery sign in other mercedez models, but they had the red light dash to begin with.. Borko maybe right and I may be wrong..

A better test would be using a battery tester. My dad bought like a $10 tester to test the battery. Just test it through where you jump start the car. If it passes the test, then it's more likely the sub battery. if it doesnt pass the test, then it could be the battery or the alternator.


And yes, i did not lose anything because I always kept one battery connected.

N_Jay

Great pictures, Thanks.


(And now you have a spare good alternator)

jangjong

Sadly, no.

Had to give it to the car parts store for "core" price. Without it, it would've been like $400..

MB-SK8

Hello everybody!!!
My wife just noticed that white battery sing this morning.
My first thoughts alternator
Than i check alternator no problem. Battery(big) new maybe 2 month old. Then reading this forum straight out my problem.
Just found battery under $60.00 original MB. Is that any other ideas for battery?
This forum really helping with any questions I have.
Thank you so much to all of you for time and effort.

C230 Sport Coup

So if you disconnect both batteries, do you experience any issues when powering back up?
I'm thinking I need to replace both on my GF's 2006 ML350.
Likely both are gone after 8 years.

C230 Sport Coup

Well, too late. Sourced the aux battery and AGM Group 48 (though most sites say group 49 for 2006) battery from Batteries Plus. FYI for $20 they'll install it for you, though I did it myself.
AAA won't sell you an AGM battery for whatever reason (though they called it an AMG battery, which briefly threw me, with me going no, it's not an AMG model! ) .
It had a Mercedes battery which leads me to believe that it could have been the original battery. Wow. 8+ years on the original.
It was fried. Anyway, no more battery error on dash, oh happy daze! Now to do the rear brakes, and fill the washer fluid.

patakka

Very helpful

gerrits

Anyone know where the auxiliary battery is on the 2012 (W166) ML350?

Thx

N_Jay

Probably the same place but ask on the W166 or X166 forum.

Keyser Soze

While changing batteries both were removed at the same time and out of the ML for over an hour. The only 'resetting' required was for the 4 windows and sunroof. From the manual: "Once a door window is closed completely, hold the respective switch 'up' for approximately 3 seconds. The door window is now synchronized. For the sunroof, press and hold the sunroof switch 'up' until the tilt/sliding sunroof is fully raised at the rear. Continue to hold the sunroof switch 'up' for approximately 1 second." All done, nothing else was affected............

spkml320

Here is the picture of the small, auxilliary battery from my 2007 ML350. I can confirm that it is ok to remove both batteries at the same time. Just sychronize the windows and sunroof to restore 1 touch open/close and that's it. No need for radio code. Radio presets not affected.

wannawagon

Sorry to revive an old subject.

Is there any definite way of knowing which battery the battery symbol message is referring to?

Is there a different message for the main battery, and the Auxilliary battery?

Maj. Dundee

The WHITE Battery symbol is for the auxiliary battery. The RED symbol is for the main battery or insufficient charging.

wannawagon

Thanks for that - very clear