testing crash sensor on 93 940 wagon

[sgtpck]

Hello,
I'm new to the forum.
The airbag deployed on my wife's 1993 940 wagon. None of the parts (air bag, sensors etc) are available new. I can get the replacement parts from a local salvage yard, but need to know how to test the crash sensors. I have heard that one can do this with a multi meter, but have not been able to find the details.

Thanks for any help you can offer.

Donald