My W164 has a battery issue. If parked for more than 2days then it won't start. If daily driven then no problems. I decided to tackle the issue by removing the battery and have Interstate Batteries check it out. This is a AGM battery and it checked out ok. The guy said I need to check out the vehicle voltage drain.
Right after I placed the battery back, I got a white battery message. Is there a fuse on the battery that just blown? I saw a fuse on the W163 but not on W164. Which fuse should I check for alternator function?

 

What year and model are you referring to?

 

This is the 07 ML63

 

Never mind. Ohms was OL on the negative wire that connect the main battery and the auxiliary battery. I believe it was 1/2 cut and broke off when I removed the main battery.

 

You definitely have a parasitic draw somewhere in the veh. and the cause of the WHITE Auxiliary Battery message is because they are attached together by battery cables.

When you removed the main battery, the Aux. Batt. noticed that there was no feed voltage, hence the WHITE MESSAGE.

To prevent future battery drain, you must remove the NEGATIVE cable on the main battery and reattach it when you want to drive it.