I have a red battery warning light on my 2004 E320 4-matic.
I had the code read & the Aux Battery is bad.
What is the exact proceedure for changing it out?
Do I need to disconnect the main battery first or can I just swap the aux battery?
I do not want to short out anything or wreck anything else.
Thanks in advance!
Tony

 

no just a basic change. just make sure the key is not in the ignition. just remove and replace.

 

Thanks!
Any sources for this other than the dealer?
The dealer is a little expensive.