Originally Posted by apkano
DO NOT PLUG IT IN!!!!!!!!!!!!
It was part of the early sound deadening system Mercedes was trying to develop. It's actually part of the passenger seat ejection unit, a little known option considered for married men only.
Silly!
No, all seats work, everything seems fine. Just wanted to know what would have plugged in there, if anything. Seems like a plug on a seat like that would have some sort of purpose.