Had the exact problem with my '92 318iC. Disconnected an accessory wire from the fuse box and the SRS light stayed on. Dealer spent 2 days trying to figure out why. Ended up replacing a bad control module at $1200. The crash sensors can cause this as well, and they only cost about $500 ea. You can shop around for these parts if needed and save some money. Anyway, you should have the system tested by 2 places to make sure they come up with the same diagnosis and then decide if the added safety is worth the repair. That was a no-brainer for me. Good luck.