Up for sale is a good used SRS sensor.  This is for Saab 9-5's 2002 2003 and 2004 2005, Right front, passenger side door.  This is located in the door, and is used for the side impact air-bag's in the seat.

Srs Sensor - 5019237

This is a good used unit.  These units list as no longer available from Saab!  Before they became no longer available, they cost $127.00 each! 

For sure diagnosis?  Hook up to the tech2 Saab tool, and it will tell you what your air bag code is for.  Otherwise, if you are having air-bag lights, this is a shot in the dark.  But... Apparently any of these sensors going bad IS a very common problem. 

This came out of a sludge car with no crash damage, and no air-bag light.