I had the same issue with my 90 300E. I replaced the battery since it was about 6 years old anyway and ordered a regulator. Same light issue with the ASR and such but not the battery warning light. Manual says that if it is not charging then the battery warning will come on, but it definately does not on my car and yours either. Cost me 32 bucks for the Bosch from Autohauz. Takes about twenty minutes while in the car. LIke this: Disconnect battery. Jack front of car and place on jack stands. Slide under and remove two screws (phillips head)that attach the regulator and brush assm to alternator and slide out. Wrap new brushes with a strand of dental floss to hold compressed while you insert. Start the two screws and cut and remove the floss. Jack car and remove from stands. Reconnect battery.
Chris
90 300E 132,000m