viperbob

I removed my passenger airbag, and of course the airbag light comes on. I had posted to see if anyone knew the proper resistor to put in place to fool the control unit into thinking it is still there. No one responded. So now my question.

I want to be 5000% careful when dealing with an airbag. Is there any issue using my ohm meter on the airbag to detect the resistance?

Gert

The resistor that you need is 2.8 Ohm.

poorb0yw

Since were on this topic. Anyone know what type of tool you are supposed to use to take off the control unit? Those round nuts are pretty tricky.

I'd like to take the sensors out as well if someone knows where those are located. I haven't gotten a chance to poke around my car in months .

viperbob

Thanks Gert... I will get one and wire it in...

Gert

You're welcome Bob.

Tom W

Bob, Get a bunch of resistors. If it works for you, I'll do it when I pull the airbags from my car. My 'new' steering wheel from Eric should arrive soon. (And as long as I'm removing one air bag, I may as well remove both.)

vm

No one answered this part of the question but yes, I see an issue. Ohm meters work by passing a voltage through the device you want to measure and then reading the current that passes through which in turn is used to calculate resistance. So by measuring the resistance you are putting a voltage through your airbag which to me sounds dangerous. Granted, the voltage is very small and may not do anything but it is extremely risky IMHO.

OldGuy

The other quesion would be what wattage resistor
does he need. The little tiny ones are 1/4 watt. then you have
1/2 watt and 1 and 2 watt and on up. you need to check that,
the little ones may burn up if they are not of the correct wattage.
Maybe Watt would know!

viperbob

VM - That was exactly my concern...

OldGuy - So not remembering any of my EE courses from 20 years ago, what would be the down side to getting a resistor with too much current capacity given a 12V source. Wait, it is coming back to me, but poorly. Current equals voltage / resistance. So OK, I'm lost again as I don't see how that relates to the rating on the resistor.

Hard to believe I use to do Thevenin Equivalents in college.....

OldGuy

Bob,
Dang I am gonna have to look in my books, if I can find them
I know for a fact Thevinen did not drink enough beer.
I think P=Vsquared/I. But I even forgot about the 1/8watt
resistors. With a 12 volt battery, you might blow the fuse
or the resistor. Thats why you need to make sure the resistor
is of the correct wattage. SO figure out with 2.9 ohms you got
I=V/R you got 12/2.8 which is around 4 amps. Which equals
144/4 is about 36 watts. Thats a helluva big resistor.
The important thing to remember here is
I have had 4 Sierra Nevada Celebration Ales, and I am sitting here
in my Sponge Bob boxers my 13 year old gave me for Christmas.
So figure the possiblity of me even getting simple stuff like this correct
is the same as me winning the lottery.
But anyway make sure you get the right size ohmage
which is french for a cheesy resistor.

chris walrod

I imagine the current being passed through that circuit is really only to check the airbags continuity. I would think a 1/4watt would be fine. I guess one could measure the voltage and then the current of the circuit with a VOM.

I would be afraid to ohm-out the airbag itself, like mentioned above.

Let us know how it turns out...

Great thread BTW

JasonAndreas

I haven't tried it myself but Porsche sells a special tool #9259 (looks like a 1/4" socket with teeth) for removing the shear-off(?) nuts.

Howdy993

A higher wattage rating only pertains to the amount of current the resistor can handle. It will make the resistor larger and possibly more expensive.
It will still do the job and be less likely to burn up.

So IMHO higher wattage is not a bad thing.

Howard
98C2 Cab tip glacier white / black top

Gert

A 1/4W resistor will do just fine.

There isn't 12V over the resisitor even during the airbag test.
Only when you crash, you might blow the resistor .

Alan C.

If you are working on an air bag make sure the bag side, side facing the inside of the car, is up. A lot of people will lay them down on the bag surface. If the bag goes off you will be presented with a face full of rapidly moving metal.