MB+

2010 GL 450, x164 production 10/2009
I recently had the aux battery malfunction sign come on dash board and took it to my local mechanic as free checkup. He determined, visually, to have it replaced as it was the original since production.
I replaced it from my local MB part/service center and did it myself, was pretty easy. (battery part: n000000004029)

The issue is that after driving 3 weeks the sign is still on despite the new battery. I called the local MB service center and they said they can take a look and take the battery back but is mandatory to run a diagnosis with the car hook up at $150. Is there a way how to remove the sign that is coming from a hidden menu, etc? No other signs were ever present or the vehicle having any issues.

dwooderson

Hey, the battery indicator showed up on our dashboard last month, so my wife took the car to NTB, they tested the battery, said it needed to be replaced, and they replaced it. This is the main battery under the passenger seat.

The battery indicator didn't go away, it's still on.

I'm embarrassed to say, I didn't know there was an AUX battery on the GL (ours is a 2008 GL320 CDI). I wonder if that's gone bad?

Did you ever get your indicator cleared?

DennisG01

Check in your manual (or download it), but I think there are separate indicators for main battery and aux battery. Also, depending on what you're actually referring to, check the alternator output at the battery - either through the dash display (see manual) or just use a voltmeter at the battery post in the engine bay, or check directly at the battery.

MB+

My volatage reads good and near 13V when checked within the MB hidden menu so it isn't the main (big) battery issue.
My main battery work and performs and holds charge well. Its the aux battery that even with a new aux battery the sign remains lit. There are fuses under the passenger seat so my next mission is to check them and see if all are up to par and not blown. MB service dealer was $150 just to run a diagnostic for the sign.

DennisG01

13V with the engine running (it's not clear from your post as you didn't clarify)? If so, you are mistaken to assume that that voltage means everything is OK. That's too low.

MB+

My mistake, while running it raises to 13.9V on a cold start and flucates up and down by a few but stays near the 14V.

My voltage of the "13.9V" is of the main battery which reads on the dashboard. My inquiry is of the aux battery which doesn't show anything in the hidden menu.