Auxiliary battery?

[Huwt5477]

Hi, I have a battery symbol that comes up on the dash of my ml 320 (2006) and been told this could be an aux battery problem, could anyone advise me on where this is and how do I check it and what does this battery do?

 

[whitenemesis]

IIRC the aux battery is under the passenger seat, under the floor.

 

[grober]

iN THE W164 model THE AUXILLIARY BATTERY is evidently found beside the main battery under the passenger [lhd] ---[rhd] drivers seat?? POST 22 Just Replaced Aux Battery - Page 3 - Mercedes-Benz Forum

 

[Huwt5477]

Many thanks peeps, but what is it for and what happens if I don't replace it?

 

[grober]

Modern cars are packed full of electronics. Think of the auxilliary battery as a backup battery to maintain vital ECU settings in the event of main battery failure. It's certainly not capable of starting the car for example. [ 12VOLT 12Ah] The factory fit ones were made by Fiamm IIRC. If either the main or auxilliary battery needs replacing - just do it. In todays electronic laden cars its a no brainer.

 

[Diesel Benz]

Actually if you look at the wiring diagram, G1/7 does not supply many control units at all. The main (and pretty much only) purpose is to backup the intelligent servo module to enable forward/backward gear range selection in an emergency (a failure on the main drive or low voltage on the consumer battery).

This small battery exists on cars that have the electric column shift. Since there is no mechanical connection from the gear stick to the tranny, a backup or emergency shift option is built in. This emergency operation is powered up by the small battery, unless the car has some other second battery like a separate starter battery (pre-facelift W221 etc.). I cannot remember if the stop/start battery also makes G1/7 redundant.

 

[Huwt5477]

Many thanks guys, any suggestions on best place to get one?

 

[grober]

Probably your MB dealer.