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trader_4 trader_4 is offline
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Default GM Ignition Switch Fault

On Monday, May 19, 2014 9:00:44 PM UTC-4, wrote:
On Mon, 19 May 2014 16:39:57 -0700 (PDT), trader_4

wrote:



I saw on a car talk website where they said a similar thing,


ie that the bags have some reserve energy to deploy for some short


period eg couple mins, after the key is off. If that's true though,


then how do you explain the GM car crashes at issue, where the airbags


did not deploy? All the media reports I've seen say it's because the


key was not in the on position.




The air bags are fired electrically and I assume they are wired to the

ignition position not the accessory position.



That's what I thought too. But according to Nestor, he found where
there is an energy reserve of x minutes, for the airbags. I found a
similar discussion:

http://www.cartalk.com/content/will-...ing-not-moving


But I think the real answer is that it likely varies from manufacturer
to manufactuer and even NHTSA is confused. NHTSA testified to Congress
that they do have a reserve, like Nestor said, but GM says it's recall cars
airbags go inactive 150ms after the key moves from run.



http://www.autoblog.com/2014/05/16/n...-airbags-work/


"There might actually be a bit of a silver lining to General Motors' ignition switch recall of 2.6 million cars. In the end, it may mean safer vehicles on the road from every automaker. The debacle has shined a light on how little the National Highway Traffic Safety Administration actually understands about airbags and their deployment. The regulator is now working to change that, and it's investigating how to make the devices even safer.

In its Congressional testimony, NHTSA said that it believed the General Motors recalled vehicles had 60 seconds of power for the airbags after their ignition switches were turned off, according to The Detroit News. The automaker has denied this - its own research has found that the bags will only work for about 150 milliseconds after the ignition has been moved from the run position.

This discrepancy between GM and NHTSA investigations may lead to major improvements in how airbags work. The regulator has begun surveying automakers and airbag suppliers to learn more about how ignition position affects activation, according to the report.

At the moment, these airbag activation parameters remain unregulated. While the pyrotechnic devices legally have to be in cars, automakers tune their deployment differently, depending on their own internal standards. NHTSA's analysis could eventually lead to new regulations determining whether these safety devices should continue to work for a period of time after a vehicle is shut off. "