Doug427

Define proper????
I took it to the local O'Reilly's. He rolled out with this big computerized machine and said battery is good.

tw2

What you had done is likely the exact same type of tool. Proper:

Doug427

Just to wrap this up, maybe it will help someone else down the road. Had the "convenience items disconnected" and the red visit workshop screen with a picture of a battery. Tested the battery with my shiny new Solar battery tester. It tested good. Checked voltage on the battery, was about 12v with no increase in voltage whatsoever when the car is started, so no charging was apparent. Took a chance and changed the regulator. No change, still bad. Bought a brand new Bosch alternator on Amazon for about $320, paid an extra $16 for overnight shipping up-charge over Prime. Just put it in today (what a pain the *** this job is), and, presto! All is well. Thanks to all for their incredibly valuable advice.

eFifty5AMG

Thanks for the update. Glad it's finally fixed.

rapidoxidation

Not gonna say it...

Fountain35

Just had the Low battery/conven. function message on my car. The car has been sitting for a while so I started the car and after about 20 seconds the message went away and it said all functions are Ok...Big battery was replaced with an OEM Mercedes battery in 2017.