This wire is continue goes to ( under R side carpet) to the trunk and end up to and un hook at battery compartment I would said PO was tryied to have continuous power supply for some new personal portable equipment at the center console but never finish, I may take this opportunity. At this time I am graful to know your are the only one who is installing a new Android to up grade cause I am serious want to have newest Android 11 car play with touch screen ( Ebay for less than $600

) but just wandering how much reliable this unit is ??) Please give me some courage

.
Damn, I could make use of that wiring then! LOL
It's now 559.99, but I got it for 429.99 on February 5th and delivered February 7th.
It is now fully installed, but I need to run a better mic and jump the GPS antenna to the factory one. I just ordered the parts for that and will do it in a few days.
So far it's mostly working, but the damn day/night auto switch by time of day light detection doesn't work. Still trying to figure that out.
I also had to buy the MMI adapter so It could plug directly into the Audio out from the Android unit.
All in all I'm happy with it.
Buy MekedeTech Android 11 Car Touch Screen Upgrade Octa 4G RAM 64G ROM 10.25 inch Car Radio Multimedia Player GPS Navigation for Mercedes Benz S W221 W216 CL 2010-2013 S-Class Head Unit (NTG 3.5) at Amazon. Customer reviews and photos may be available to help you make the right purchase decision!
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Edit:
Now would be a great time to get one since you have all the correct parts removed to do the full install. LOL