Rapsteady1

Good afternoon MBZ fam,

I had a quick question regarding the "2nd passenger airbag light" located on the bottom of the emergency lights. (I am driving a 08' c300) Is this supposed to be lit at all? When I have a passenger sitting in the front, the lights go away, but when I'm driving alone, it turns on. Isn't the airbag always supposed to be turned on regardless of there being a passenger or not?

Thanks in advance for the help,

-thm, m.d.

Sportstick

It is functioning correctly. Why would you want to blow the passenger bag, necessitating an instrument panel replacement, if you were driving alone? You would derive no benefit as driver and the costs would be high and wasted.

Rapsteady1

If I'm paying good money for a car, I would want all the airbags to work (Driver, passenger, back sides, etc) if I were to be in a car accident.

Shouldn't it be irrelevant if i have a passenger or not? That airbag should work regardless. I'm not worried about costs, thats what my insurance is for.

jeancarlo

obviously is a problem, an anormal problem, maybe the seat is in bad form, but for more information you can vist Rockautos.com

Sportstick

With sincere respect for your opinion, you may not fully understand the function of the inflatable passive restraints. I retired from a major auto manufacturer and spent 6 years in the vehicle safety office. I can assure you that a wide variety of factors developed between the international auto industry and the National Highway Traffic Safety Administration went into designing this set of performance standards. The air bag performance intends to have an adult of at least a certain weight in position so that g force loads to the chest and head are properly reduced. In this case, proper function is for only the air bag at an occupied position to inflate.

By analogy, although somewhat tortured, you might also say that you paid perfectly good money for brakes, a critical safety item, and you want them not just ready to engage, but engaged all the time! I realize that sounds absurd, but from an engineering perspective, inflating a car's worth of air bags for a single driver seems similar.

I also note you are comfortable with the actually wasted cost of unneeded inflated bags being handled by insurance, but that just means everyone gets to pay and many are not as comfortable with supporting waste as you may be.

You should drive your MB with good confidence that you have one of the best safety engineered vehicles in the world, perhaps only second to vehicles benefiting from greater mass. And, no, I do not and never worked for Mercedes.

snarlingchicken

Well said. Basically, MBZ decided to save it's buyers the cost of having to replace an unnecessary airbag deployment/dashboard cover in the case of a crash.The airbag is fully functional, but only inflates when it is necessary (FOR THE PASSENGER). If there is no passenger, then there's no need for the passenger airbag to go off is there?

Rapsteady1

Thank you sir for clarifying, I was paranoid with the new technology. After reading the message that popped up in my dashboard about something regarding airbags, I thought that something went completely wrong.

mr inkredibul

It because people put kids in the front seats and the airbags kill em. So there is a weight requirement to make the airbags go off. Its an added safety feature.

phatboypimp

^^^^^^ ding ding ding

Sportstick

The OCS (Occupant Classification Sensor) in the front passenger seat inhibits or modifies rate of inflation based on the weight in the seat it identifies. Rate of inflation is reduced for low weight occupants and does not "kill 'em". The OPs original issue of why all the bags in the car don't blow goes beyond that issue.

mr inkredibul

So tell me what inflation rate is the right one for a people who still put child seats in the front. ANY inflation rate will kill a kid under 8, thats why they aren't supposed to right in the front.

Sportstick

That is not necessarily true. Factors to consider include the variation in height, whether the child is in or out of proper seating position, how far forward or back the seat is placed. A 95th percentile 8 year old, sitting in position with the seat at full rear track travel faces a different risk than the opposite for each of those conditions. In order to reduce risk across a full population, the standard recommendation is to place all children under age 12 in the center of the rear seat, which is the best practice.

The frequent fatality which occurred among children and short females when air bags were first launched was a basilar skull fracture. This would occur when the air bag impinged on the neck just below the chin before being fully inflated, and the inflation process would lift the head off the spine, fracturing at the base of the skull and severing the spine at a level incompatible with survival. Rearward facing child seats should never be placed in the front seat, as they intrude directly upon the instrument panel.

Subsequent air bag design was able to modify the inflation rate to accommodate the weight and correlated size of the occupant. But, the reason for not deploying an air bag for a completely empty seat has a large economic component to it.

I appreciate and support your implied concern for safety and agree that kids should ride in back, but as we were discussing the technical background, I thought I'd share some info from one of my positions in my earlier automotive career.

mr inkredibul

^^^ You obviously know far more than anyone on here about that subject but the airbag still shuts off at a certain weight. Are you telling me that if I put a 3o pound 3 year old that the airbag can deploy at a safe enough speed to not injure the chile?

Sportstick

With this discussion subject, I am not giving anyone advice nor information upon which they should rely or act.

But, Absolutely Not.

We often received a question from owners asking what vehicle is "safe". Our answer was that there is no "bright line" which separates "safe" from "unsafe". Rather, one should think about safety as decisions to manage and reduce risk. For example, smaller cars may avoid an accident through enhanced handling vs. the trade-off of lower mass if actually in an accident. And, each decision usually has trade-offs which require analysis before simply implementing them based on face value.

For your question, all the data makes it clear a 3 year old's risk is greatly reduced by sitting in the center position (furthest from side impact intrusion) in the rear. A minor downside is that the child may be more difficult to reach post-impact if seated alone in the rear, but that is more than offset by the enhanced statistical survivability of that position. Further complicating the matter, not every 3 year old improperly seated in the front will suffer fatal injuries from an air bag and not every 3 year old properly seated in the rear will survive every crash. This is a matter of taking prudent steps to improve the likely outcomes, so we can not look for guaranteed results in either scenario.

Hypothetically, and not offering any advice to anyone, if I had a 5 passenger car and absolutely had to travel with 4 children all under the age of 12, one way I could reduce overall risk (other than not traveling) would be to select the tallest child, push the passenger seat all the way to the rear of the track (FMVSS testing is done with seat at mid-track), and ensure that the child seat, booster, and/or seat belt is properly and snugly applied and that the child sat straight, did not lean forward for the radio, etc., and alter my driving style. Those actions reduce, but don't eliminate, risk and cannot make a scenario "safe", as that absolute condition does not truly exist. But, absent that contrived 4-child situation, the risk/benefit analysis would always have all the children in the rear.

The point I was trying to make earlier was that an algorithm which inhibits deploying the bag with zero weight has a major economic component. The decision to blow/not blow the bag, and the rate of inflation, when there is modest weight in the passenger seat clearly has other factors involved.