My auxiliary battery light has been on for while. MB dealer wants to charge me $175 for the battery and $145 to install. Seems kind of pricy because the install doesn't' look difficult. They charge for an hour of labor, do the install and do a system reset. Which they say "reprograms the computer to let it know there's a new battery as to not overcharge it". Does this reset need to be done? I've watched many videos and none talk about the system reset. A few talk about how to reset, synchronize and calibrate the various electronics like windows, sun roof, steering etc. after changing a battery which seems pretty easy. Thanks!

Nobody else has mentioned a “reset” I think it’s to “reset “ your wallet ! You can probably get a 50$ battery and save 250

LOL that is exactly what I am thinking!! Thank goodness my local car shop is buying the software to clear codes on the newer Mercedes. Then I can be done with the dealership. I had to suck it up today and pay $245 for Service A which is basically an oil and filter change, so MB can clear the service code. :O

I changed my Aux. battery not too long ago. Paid less than $60.00 for a non-Mercedes AGM battery. Probably took me an hour to change it - cleaning out the trunk, taking my time, being careful etc. Nothing to reset, no codes to clear. The system recognized the voltage was now in the right range so no more Aux. battery warnings. I did NOT disconnect the main battery when doing this work but I don't think that would have caused any complications, had I done that. - 2014 GLK350 U.S. spec.

I didn't have the aux battery warning but I replaced my main battery and was thinking my aux had never been changed. I bought the aux at o'reilly for $100. Took me about 15 mins to change it. Didn't remove power from the main. The old Aux was from 2012, so I figured it was about time.

I agree, with the previous responses. I had the light come on, I purchased an AGM battery of the same Spec on Amazon for $45.00 ish. It arrived the next day and I installed it, the actual task takes 15-20 minutes total, but I did it 2 phases. In my car, 2014 GLK 350, it took a few days for the ECO system to get back in the game. I too thought there might be a "reset" procedure needed, it was not, I'm not sure why there was a delay, but now the system works as before. I would recommend doing it yourself, if you are at all handy. The only tricky part is finding all the fasteners that hold down the plastic "trim / surround" that covers the Batt., cables, etc. But be cautious and they reveal themselves