JKOwners Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
459 Posts
Discussion Starter #1
So, after a discussion at work one day about airbag sensors my friend and I concluded that.... we diddn't know the answer. So.... where are the front airbag sensors? and how do you think the get affected by putting an aftermarket steel bumper on? Not that it's detering me from replacing my bumper.
 

·
Administrator
Joined
·
8,749 Posts
So, after a discussion at work one day about airbag sensors my friend and I concluded that.... we diddn't know the answer. So.... where are the front airbag sensors? and how do you think the get affected by putting an aftermarket steel bumper on? Not that it's detering me from replacing my bumper.
I'm pretty sure there is no "Airbag Sensor" per say and that the system works on digital accelerometers.
 

·
Registered
Joined
·
2,012 Posts
There are no sensors located in the bumpers of the JK. I know this from recently replacing my bumpers.
I believe I read somewhere that the sensors for the airbags are located somewhere in the dash. And like Hit said, I would imagine that they are some sort of accelerometers, and not actual 'sensors'.



AMP
 

·
Premium Member
Joined
·
3,068 Posts
The airbags in the JK work off of an accelerometer that is located in the center of the vehicle under the center console. Specificaly the sensor works in conjunction with a yaw/pitch/roll sensor (same function as a gyroscope) that is co located. If the deceleration and pitch, roll or yaw of the vehicle hit certain thresholds the specific airbags and the seat belt pre-tensioning charge are deployed as needed. There are no "contact" style sensors located on the vehicle, it is all based on the two sensors located centrally. The pitch, roll, yaw sensor also feeds into the stability program.

The perpose of the bumpers in stock form is to deform over a given time (remeber we are talking 10thousandths of a second here) slowing the deceleration of the vehicle, in conjunction with the frame relief (crumple zones). By spreading the force of the impact over a few thousands of a second and a few inches of crumple space you can realisticaly reduce the peak G's in an accident by a factor of 10. Aftermarket bumpers in theory (with there overall lack of deformation) would cause your airbag to be more likley to go off than the stock set-up, but there are so many factors that feed the equation it is really hard pinpoint how much more likley it would be.

Example (basic as it may be, numbers are simply used for illistration):

If the airbag deploys in a frontal colision when the sensor detects 800 peak G:

Hitting an imovable object at 15mph with the factory set up may only generate 750 peak G

While hitting the same imovable object with an aftermarket (non deforming) bumper at 15mph may generate 1100 G

In this case the aftermarket bumper would cause your airbag to deploy where as the factory set up would not because the factory set up deformed to absorb the force of the impact.
 
  • Like
Reactions: stretch79

·
Registered
Joined
·
2,012 Posts
^^ Very informative and factual post 09rubicon.

:beer: to you!



AMP
 

·
Registered
Joined
·
3,105 Posts
09rubicon Thanks

I've been thru this already. Thanks for an exact answer.

YOU ARE CORRECT SIR !!!!

:beer::beer:
 

·
Registered
Joined
·
459 Posts
Discussion Starter #8
BRAVO! I thought it was some kind of deceleration thingamagig, that was a great response. Thanks for the info.
 

·
Registered
Joined
·
11 Posts
The '07 JKU has front impact sensors. They are covered in the service manual.

From the 2007 Service Manual:
Two front impact sensors (1) are used on this vehicle, one each for the left and right sides of the vehicle. These sensors are mounted remotely from the impact sensor that is internal to the Occupant Restraint Controller (ORC). Each front sensor is secured with a screw to the back of the front end module carrier on either side of the cooling module and inboard of the headlamp within the engine compartment.

The front impact sensors are electronic accelerometers that sense the rate of vehicle deceleration, which provides verification of the direction and severity of an impact. Each sensor also contains an electronic communication chip that allows the unit to communicate the sensor status as well as sensor fault information to the microprocessor in the Occupant Restraint Controller (ORC).
 

·
Premium Member
Joined
·
3,068 Posts
The '07 JKU has front impact sensors. They are covered in the service manual.

From the 2007 Service Manual:

Good to know, wonder if the 08 is the same? I know the 09 does not have the frontal sensors, neither does my new 11.

The above statement still stands true, the sensors are not impact sensors per se. They are decelerometers that measure deceleration to sense an impact.
 
1 - 11 of 11 Posts
Top