Up for sale is a good used SRS sensor pair.  Saab 900 Impact sensor pair, left and right. 

Srs Sensor - Genuine SAAB 4079174 and 4079182

Once the Air-Bag ECU has detected a fault, it will always illuminate the SRS light, even once the fault has been repaired, and even after disconnecting the battery overnight. You need to have the system fault cleared at a dealer or independent saab shop with either the Saab Air-Bag tool, the "ISAT" or tech-2 with the proper attachments. This should only take about 2-5 minutes, but it IS the only way to clear an SRS fault once the light has been triggered on old style SAABS! My Saab technician would usually do this for me at the price of a case of beer.  you need to do proper diagnosis with the iSat, figure out which sensor is bad, replace that sensor, and re-set the system.  You will then have a functional air bag system again.  I have this listed for the PAIR for about 1/2 the price of a single new one from Saab.