GDawgC220

My SRS light has been on for a while now. When I start the car, it will stay on for approximitley for 2 minutes, then shuts off. My service advisor tells me that this is a delay for those two minutes and if an accident were to happen within the two minutes, my airbag will not come out. But, after the light goes out, the airbag will operate normally again?

Anyone know of this or mechanics here?

BTW, it is a belt buckle relay (drivers side) that is malfunctioning at this point...

BadAssBenz

The same thing happened to me afteR I swapped out my interior for black leather. The light would come on for a couple minutes and then go off. I got the SRS module under the hood reset and it was fine after that. I think it had something to do with a sensor that plugs into the seat to detect if someone is sitting in the seat or not.

blackmercedes

There is a sensor for the driver's seat buckle (there is no occupancy sensor for the driver's seat, as the car assumes it's always occupied when driving). This sensor determines the threshold for bag deployment. If you (are a moron) and drive unbuckled, then the bag deploys at a lower speed and impact level than if you were belted.

If the buckle sensor has failed, the bag's computer may be unable to determine the proper threshold, and will light the SRS warning lamp. This is a common W202 fault, and often brought on by food or liquids being spilled into the buckle receptacle.

Sometimes you can trigger the lamp if you turn the key on while one of the seats is out of the car as well.

As to the SRS system and the warning lamp, your mechanic is right. While the lamp is lit, the bags will not deploy and the ETR's will not fire. The inertia reels in the seatbelts are still operating, so you'll have protection in a crash, but no bags or ETRs reduces your passive safety systems at work.

GDawgC220

So when the light shuts off, does that mean the systems are back to normal and I have airbag protection in the event of an accident? (that's what my service advisor told me, that it is a delay in the airbag system)

Rincewind

wow thats really neat.

i never knew that heh

vas2vas

my 95 c280 does the same , the SRS light stays on for 2 min after starting, (this is how I got the car), and I haven't looked into it yet because as long as it goes off I'm leaving it alone!

GDawgC220

Does anyone know if it (airbag(s)) go off in an accident after the light goes out??? I know during the light remains lit, no airbags, but afterwards...

blackmercedes

Hold yer horses, we're getting there.

Yes, the SRS system is functioning properly when the SRS warning lamp is not lit. Both the bags and the ETRs will fire normally. A Mercedes airbag primer...

1. Mercedes and BMW are the only manufacturers in the WORLD not to have recorded a single mis-deployment of an airbag. It's because MB spent huge reseources into engineering bags from the first day, and BMW was brilliant and copied them. For those that cry foul, know that Mercedes REFUSES to enforce patents on safety devices. Every car maker was free to copy MB's superb system.

2. The reason they have this record is that the bags are designed to deploy in very certain collisions. Most makers bags deploy anytime the car strikes something. Not MB. If you are rear-ended and the forces are to the rear of the car, then you don't need a bag on the front of the dash. If the forces change during the collision and are high enough in a different direction, then a bag may deploy. MB's bags don't go off is you tap the car in front of you or bang into a curb.

3. MB was the first to have bags deploy in different ways at different times. They still understand that your seatbelt is the primary safety device in the car, and the bags, are, well, "supplementary." (hence the SRS name) Because Americans refused to do up their seatbelts, airbags were legislated in the US, and every maker had to put them in their cars. Well, of course some cars are junk and so are their airbags. Chrysler sold lots of low end cars with low end bag systems that would deploy even if you just ran into a curb. We had a high-profile case here where an eight year old girl was killed in a Chrysler mini-van thanks to a low speed low impact bag deployment, which leads to #4...

4. Don't put your kids next to airbags. NEVER. A bag deployment, even the so-called Gen II bags, will kill them. I wish that it would be illegal and classified as child neglet, as that is what it is.

GDawgC220

Good, as long as the system works after the light goes out in 2 minutes. Does this problem really have to be fixed if the system is back to normal after 2 minutes...? I think my dealer quoted be about $400 for the buckle and labor...

vas2vas

to tell you the truth the airbag WILL go off even with the srs light on!
I have personally tested the theory!
in my case one of the sensors was faulty but the airbag worked anyway.....even though I was told by the dealer that it wouldn't.....which was quite a pleasant surprise since the seatbelt broke loose! bosch/siemens airbag systems that were installed on most german cars are pretty robust examples of german technology!

zdzich

Does anyone have a wiring diagram for SRS system in 97 C280 ? I bought a car with driver airbag deployed. I replaced the airbag, driver seatbelt, and the control module. When I turn the ignition on the SRS light goes on for a couple of seconds then goes off and after a moment comes back on again. I need the schematic to check the wiring.