Front Passenger Airbag light not on when child is in front seat... is this normal?

[MIKI]

Hello,
This is my first post on this forum. I own a 2010 GLK350 4Matic, and have noticed that the middle console SRS light indicating "front passenger airbag OFF" light is never lit. It used to be lit when there was no weight on the seat, and now I have a bunch of kids I have to drive around. I will need to stick one in the front seat at one point or another, and I have no way to tell if the passenger airbag is off or not. I have been told that the light should only flash when the car is started, and then remain off... My manual tells me it should stay on when the weight is not sufficient to activate the airbag.
I took the car to the dealer, (covered under extended warranty,) and they replaced the sensors in the front seat pad... I have the car back now, and the light is still not coming on, (other than flash at start up,) even when seat is empty...

When I forwarded a copy of the manual, I was told this does not apply? Why do I have this manual?

Any thoughts? What is the real deal? I don't want to jeopardize the safety of my child.

Thanks!

 

[Simatim]

Just my thoughts on this issue and nothing certain but I'm thinking that the light is staying on because the weight that is sensed in the seat is not enough to activate the airbag. As small children are not advised to be in the front seat as airbags can actually do more harm that good for them, I would imagine the airbag is only active when the sensor read that the eight is at a certain amount.