I am new to MB and have a 2000 SL 500 (129). On the side of the passenger seat there is a switch that in on position is blank and another seems to show a child. I can't find it in the manual that I have. I expected that it was a child lock for the door but when I tested that it was not. Then I thought that it may be a switch to turn off the airbag but the airbag light does not come on when the switch is in 'child' mode. What does this do?

 

locks the seat belt. from extending more

 

It is used to lock the seat belt when a child seat is installed.