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Passenger seat airbag sensor?

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92K views 20 replies 12 participants last post by  Bimmer0  
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#1 ·
What's the best solution to get the light on the dashboard to turn off but keep the airbags working?

I've heard / seen on the web several solutions.

Can someone please link me to the best solution on e-bay or other.

In addition, can the solution be fit in without taking out the passanger seat? I heard in some models it can and some it can not, how about the E39?

Thanks

S.G
 
C
#2 · (Edited)
In most cars, the pass seat sensor is there to detect weight. If less than lets' say 40 lbs, the air bad does not deploy to prevent injury to a child or car seat (BTW, baby car seat should be in the back seat!).

Assuming the airbag light points to the passenger seat sensor, you have 2 options:

1. Replace the sensor (it is expensive).
http://www.bimmerboard.com/forums/posts/291770

2. Repair the diode/reistor, See post #5 carefully. It is a $10 fix:
http://www.bimmerfest.com/forums/showthread.php?t=406087

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#3 ·
The airbags will still deploy. In fact...in the event of an accident...you may get more airbags deploying than what would be necessary (better safe than sorry).

The default when the SRS/airbag light is illuminated...is to deploy the bags...not to shut them all down. If there was litigation due to injury...the case would more than likely side with BMW. Their claim would be that the SRS light illuminated warning the owner that their was an issue with the system...and if they did nothing to fix the problem...BMW is not in neglect...that will fall in the lap of the owner.

If BMW designed the system to NOT deploy...then neglect and fault could fall into BMWs lap.

For example, the "normal response range"...would mean that a faulty passenger mat sensor would deploy the bag regardless if anyone is sitting in the seat or not. The "normal response range" would be...the airbag would NOT deploy if no one is sitting there:

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C
#4 ·
If you byapss the sensor, then in the event of a collision, the airbag will deploy REGARDLESS if there is a passenger or not.
This BMW pass seat sensor is overdesign.
Small kids and car seat MUST be placed in the back anyway.

Another cheap fix is available for $25. Ebay search: "bmw air bag seat sensor".

"The prefabricated part substitutes for the seat mat and simulates to the seat occupancy electronics an occupied front passenger seat. Therefore the front seat passenger's air bag releases with a crash in ANY FALL, even if nobody has taken a seat on the seat."
http://cgi.ebay.com/ebaymotors/BMW-...tem33567dc634QQitemZ220494415412QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

FYI: My 1998 Volvo V70 has NO pass seat sensor!
 
C
#7 ·
I'd to retract my statement above re pass side air bag, kids less than 40 lbs.

The main reason for pass side occupancy mat sensor is "cost of repair", which I disagree with because any collision that sets off the airbag is likely to result in the car being totaled. Anyway, here is the reason behind the pass side occupancy mat sensor:

http://www.sae.org/technical/papers/960226

"Due to the increasing amount of cars equipped with passenger airbags, there are now a larger number of accidents during which passenger airbags are activated although nobody is actually sitting in the passenger seat. Even when one discounts those accidents which result in car "write-offs" , the unnecessary deployment of the passenger airbag increases repair costs in an unjustified way. In order to avoid this type of situation, all BMW vehicles as of June 1994 are equipped with a seat occupancy monitoring system (SOMS installed in the passenger seat.)"
 
C
#8 ·
So I did some more reading on pass side sensor issue. It is basically a safety issue and not a cost of repair issue:
Air Bags & Crash Sensors
http://www.aa1car.com/library/airbag01.htm

"Air bags have been in the news in recent years because of deaths that have resulted from air bag deployments in relatively minor low speed crashes. The victims have been small children or infants in the passenger seat, or small female adults drivers who were too close to the air bag or unbelted when it deployed. The deaths, in some cases, have been blamed on improper use of infant seats or not using seat belts. But others blame the deaths on government regulations that require auto makers to use air bags that deploy with sufficient force to protect an unbelted 160 lb. male adult in a 30-mph crash. This requires deployment speeds of up to 200 mph, which can cause serious injury or even death to children and small adults who are not buckled up or are too close to the bag when it deploys. In Europe, where rules allow air bags that deploy with 30% less force, there have been no deaths attributed to air bags.

The National Highway Traffic & Safety Administration (NHTSA) has reviewed their regulations and now allows auto makers to use less powerful air bags. NHTSA now allows auto makers to add switches for deactivating the air bags, and even allows consumers to have a switch installed (by a professional) to deactivate their air bags under certain circumstances. The auto makers are also developing smarter "adaptive" air bag systems that can vary their deployment speed and force depending on crash circumstances. Such systems modify air bag deployment force based on occupant size, seating position and impact speed.

For more information, see NHTSA's website information on Air Bags & air bag on-off switches

Regardless of what type of air bag system a vehicle has, though, all motorists are urged to use their seat belts, to sit as far back as possible from the steering wheel, and to put infants and children 12 and under in the back seat."

BONUS: Read the article and watch the video at the bottom of the article when some fools decided to sit on the airbag when it deployed!
 
#11 ·
cn90 said:

http://www.aa1car.com/library/airbag01.htm
BONUS: Read the article and watch the video at the bottom of the article when some fools decided to sit on the airbag when it deployed!
Click to expand...
Oh oh, now we're going to see big yellow warning stickers "Do not sit on air bag"!

Seriously though, since I often seat young children in the front seat, do our E39 airbags deploy with less force when they have (say 60 to 100 pounds) lighter people sitting in them?

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#10 · (Edited)
There is another cause of the airbag light coming on that I have not seen mentioned here. If you remove the passenger seat for any reason (say to access fuses 107-113 iirc which are hidden under the carpet below the passenger seat), you will have to remove a very fine stainless steel wire that is hooked to the seat frame itself. At the other end of this wire is a linear position sensor with a recoiler that keeps that wire tight. As the seat is moved forward, the wire unwraps or is pulled out of the linear position transducer. As the seat is moved toward the back seat, the wire is coiled back up much like a seat belt retractor. This position transducer tells the air bag system exactly where the passenger seat is relative to the air bag itself which somehow modifies which bags go off or how they go off if say the passenger is way up forward close to the glovebox. If this wire is removed at any time while power is still hooked up (battery not disconnected) you will set the airbag light and only hooking the wire back up properly to the seat frame and then doing an error reset to the airbag system will clear the light. I learned this the hard way. :thumbup:
 
#18 ·
might get more specific answers by posting in the e60 subforum, as thats your chassis type
www.bimmerfest.com

E60 / E61 (2004 - 2010)

BMW 5-Series E60 Sedan was first seen in the Unites States in the fall of 2003 with a 2004 Model Year designation. The E61 wagon followed shortly there after. The E60/E61 5 series is now available as a 528i, 528xi, 535i, 535xi, 550i and a 535xi sports wagon! -- View the E60 Wiki
www.bimmerfest.com www.bimmerfest.com
 
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