Like the other answerer said, it's your relay. If you look in the fuse/relay box under your hood there's one relay that is orange. This is the lamp control relay and it's one of the most well-known trouble spots on all Saabs made after 1994. Try wiggling it around, but you're most likely going to need to take it out and replace it or re-solder all the tiny little solder points in the thing. In my opinion it's worth the money (~$80) just to replace the darn thing. If you have another Saab (any model) newer than 1994 you can swap that orange relay in and see if it fixes your problem, although I'm almost positive that's what's going on for you.