R129 Passenger Airbag Light On, help!

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madbonky

Active Member
Joined
Oct 3, 2006
Messages
63
Location
Heathrow
Car
R129 300SL, ML 320, C240, CLK 500 CAB, W203 ESTATE W126 500 SEL R129 320
Hi all, I have a 2001 320 R129, the passenger airbag light started to come on recently, sometimes it goes off if someone sits in the passenger seat but otherwise stays on most of the time. I am guessing the occupancy sensor/mat that is in the seat base may possibly be at fault, has anyone got any suggestions on how to solve this without replacing the occupancy mat, i have seen emulators advertised which plug in to the airbag under seat connector and claim to trick the car into thinking someone is in the seat with the seatbelt on, does anyone have any experience of these at all? Any help greatly appreciated, thanks Jas!
 
These emulators actually tell the passenger air bag to deploy in any event in a crash and are actually used by companies like recaro etc. Fixing is obviously better, but it's not a disaster to use one.
 
Worth noting though that you wouldn't want the airbag going off with a baby/small child in the seat so I'd be fixing it rather than fooling a complex system.
 
These emulators actually tell the passenger air bag to deploy in any event in a crash and are actually used by companies like recaro etc. Fixing is obviously better, but it's not a disaster to use one.
Can it tell when a child is in the seat or or in a child seat facing the 'wrong' way ? Also one extra airbag going of unnecessarily could take a small bump from a 'fix it' to a write off.

Fix the fault.
 
Worth noting though that you wouldn't want the airbag going off with a baby/small child in the seat so I'd be fixing it rather than fooling a complex system.

The handbook for my '97 SL says to move the front seat fully to the rear when a child carrier (forward-facing only) is fitted - as demonstrated by BTB Junior below. There's no way to disable the airbag if there is weight on the seat.

pic 15.jpg
 
Also one extra airbag going of unnecessarily could take a small bump from a 'fix it' to a write off.

Fix the fault.

I agree it should be fixed although you actually need a fairly substantial impact to trigger airbags (and even then it depends on the direction etc.).
 
Its his car :) Just supplying information. If I had a 129 I would replace the mat. Its a P.I.T.A job but certainly D.I.Y able !

I love faffing about putting seats in where they are not supposed to. When I had my prefacelift W202 and retrofitted a set of C43 seats the passenger air bag sensors were not compatible so I removed the sensor from my old seats, deconstructed the C43 passenger seat. I had to remove a large part of the seat foam to fit the prefacelift box in the C43 seats. The system then worked as it should. I did this because at the time I had smaller children and needed it correct. Later on when I had a E46 and retrofitted M6 seats the occupancy sensors were not physically interchangeable so had to use a emulator but the children never sat in the front. When I sold the car I removed the seats and reverted the air bag system to standard.

So in response to the OP's original question yes you can just use a emulator but its not a perfect system but certainly not unsafe so long as you are aware of the implications and use the car accordingly.
 
The handbook for my '97 SL says to move the front seat fully to the rear when a child carrier (forward-facing only) is fitted - as demonstrated by BTB Junior below. There's no way to disable the airbag if there is weight on the seat.

View attachment 93181

You can use the Mercedes-Benz child seats with the built in transponders to turn off the airbag in the front seat, or buy them separately for your own car seat.

As above, I would fix the fault and look after BTB Junior.


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You can use the Mercedes-Benz child seats with the built in transponders to turn off the airbag in the front seat, or buy them separately for your own car seat.

Older cars (like my '97) don't have this - if there's something on the passenger seat then the airbags that side are live (unless you start cutting wires :D). But the seats do go back a long way, so I was happy that the instructions in the handbook were OK.
 
Older cars (like my '97) don't have this - if there's something on the passenger seat then the airbags that side are live (unless you start cutting wires :D). But the seats do go back a long way, so I was happy that the instructions in the handbook were OK.

Okay, I have a 98 and it works fine in that, so just presumed it would in yours. Just look after junior, who will hopefully remember the “old fashioned” car.
Sent from my iPad using Tapatalk
 
Hi all, I have a 2001 320 R129, the passenger airbag light started to come on recently, sometimes it goes off if someone sits in the passenger seat but otherwise stays on most of the time. I am guessing the occupancy sensor/mat that is in the seat base may possibly be at fault, has anyone got any suggestions on how to solve this without replacing the occupancy mat, i have seen emulators advertised which plug in to the airbag under seat connector and claim to trick the car into thinking someone is in the seat with the seatbelt on, does anyone have any experience of these at all? Any help greatly appreciated, thanks Jas!
Hi mate.

How did you fix this issue?

I have the same problem and I don't know how to fix my issue.

My MOT is also due soon.

Hope you can help.

Thanks
 
Hi mate.

How did you fix this issue?

He last visited over 2 years ago so don't hold your breath for a reply!

1685306007165.png

Somebody else may possibly be able to advise though.
 

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