Good morning I’ve been experiencing some gremlins with electrical components in my 2017 Mercedes GLS 450. I’m trying to track down where the auxiliary battery is located. It does not appear to be in the battery bay under the passenger front seat any other locations I should check?

 

2017 GLS450 (166) Aux battery is a small size in a snap in holder with clip power connections LOCATED rear passenger side below deck rear next to tire well ... in front of wolfer speaker.
MB battery N000000004039 ($ 52 AND UP) 12V 1.2 Ah
Lift spare tire lid ... from rear on right side (passengers side) there are (2) Two plastic snap clips hold the tire well carpet to the frame. Carpet can be pulled down to get access to battery.