Auxiliary Battery Malfunction

[Nigel44]

Hi
Can someone help.
where is the Auxiliary Battery located on my 2012 S Class 350 blue tec
Thanks

 

[ianw19]

I'm not sure about an S, but my 2012 E350 has it in the boot next to the spare wheel

 

[Nigel44]

Thanks - it’s defiantly not in the boot, thanks for the picture much appreciated.
I will check under the drivers side dash or in the passenger side foot well
Nigel

 

[SclassOwner]

message me your vin number and I can tell you where it is, I have access to mercedes WIS & EPC software.

I can email you a PDF file with the replacement instructions from WIS.

In W222 sclass its in the boot in the driver side you need to remove the side panel and loosen the fuse box, not sure about the W221.

 

[Nigel44]

Thanks that will be most helpful - I am working at the moment will message after 12.

thanks again for the reply

Nigel

 

[Nigel44]

Hi
The VIN number is WDD2210262A476141

thank you
Nigel

 

[Hakon]

In my E estate, the Aux battery is hidden behind the passenger glove box.
My version of WIS has no mention of this location and only mentions the saloon location, which is in the boot.
Not the only item my WIS seems to lack

 

[Nigel44]

Hi Hakon
Thanks the reply.
There is so many places it can be, hopefully I will get the answer before stripping anything out. Too many different Mercs lol

 

[Atavus]

I’m sure I mentioned the Rescue Assist QR code in the other thread.

 

[Nigel44]

I’m sure I mentioned the Rescue Assist QR code in the other thread.

Thanks Atavus - much appreciated

 

[OneForTheRoad]

I’m sure I mentioned the Rescue Assist QR code in the other thread.

I scanned mine just now , its on the passenger side pillar. Worked a treat.

 

[Nigel44]

Thanks for the reply - I will check tomorrow is yours an S Class CDI blue tec what year buddy, mines 2012?

 

[OneForTheRoad]

Thanks for the reply - I will check tomorrow is yours an S Class CDI blue tec what year buddy, mines 2012?

No mines a 2017 c207 / e350 bluetec.

 

[Nigel44]

No mines a 2017 c207 / e350 bluetec.

This is behind the back seat tested it on the meter is charging at 14.3 and reads 12.7 engine off - looks ok

 

[Nigel44]

View attachment 105102This is behind the back seat tested it on the meter is charging at 14.3 and reads 12.7 engine off - looks ok

My question now is do I change it, although its seems ok - I am not sue what the crank reading is as cant test this. what the verdict guys?

 

[wongl]

My question now is do I change it, although its seems ok - I am not sue what the crank reading is as cant test this. what the verdict guys?

Have you tried charging the aux battery with a battery charger?

 

[Nigel44]

Thanks all for your input - Battery behind right hand side back seat - changed Battery no more error messages.
So anyone who has an S Class 350 CDI blue tec 2012 with the same issue, this thread should help. Even if the battery is showing 12 volts out put and charging at 14.6 volts it could be a dead cell that causing the issue.
thanks again

 

[Nigel44]

Have you tried charging the aux battery with a battery charger?

Thanks - problem solved, I had a dead cell in the battery