Thread: "Touching Cables" Doesn't Work
05-12-2004, 08:17 PM #1
"Touching Cables" Doesn't Work
Just to make sure all of you, especially vehicle rescue instructors, have the background on an old Urban Legend, here we go one more time.
Question from a Connecticut Fire Officer:
I am the Training Captain. I received a call from someone in the FDNY safety division about deactivating airbags. They had heard that we had a policy of disconnecting the battery and then taping the two wires together to discharge the capacitor. That is in our policy, but no where can I find the documentation for doing that procedure. It was suggested that it may have come from one of your articles. If that is true, is this still a good procedure? Any help you could provide would be greatly appreciated.
To set the story straight, here's the background of how this idea of cutting battery cables and touching the red to the black got started. . . . .
Touching is ineffective today so don't waste your time.
There were three (3) models of Ford vehicles (1989,1990, & 1991 model years) with driver's only airbag that had some of the first, crude designs of airbag electrical systems. In those three models, it was OK to touch the positive to the negative cable and drain the capacitors.
Somehow, this recommendation actually made it into the Maryland state extrication training course student workbook. This is back in the early 90's. In fact, it made it through several reprints. The way the info was presented however, it left you with the impression that this touching thing worked on ALL vehicles, and that wasn't ever correct.
Forget about it. With today's airbag-equipped vehicles, the diodes within all airbag electrical circuits act as one-way check valves and prevent any backflow of electrical energy from the capacitor. It only drains by decay; elapsed time results in loss of stored energy. The typical "drain time" for a new vehicle is 2 minutes to 5 minutes. Some 2004 models even have a one second capacitor drain time!Ron Moore, Forum Moderator
05-12-2004, 08:57 PM #2
never heard of it ...........wont do it ........... thanks !IACOJ both divisions and PROUD OF IT !
Pardon me sir.. .....but I believe we are all over here !
ATTENTION ALL SHOPPERS: Will the dead horse please report to the forums.(thanks Motown)
RAY WAS HERE 08/28/05
LETHA' FOREVA' ! 010607
I'm sorry, I haven't been paying much attention for the last 3 hours.....what were we discussing?
"but I guarentee you I will FF your arse off" from>
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