Indicator light will not go out

I have a 1992 Audi 100cs.A light on the dash won’t go out (looks like a crossed out bomb) and flashes “brake light” every now and then with a ding sound. I replaced the bulbs for the brake lights but this did not change anything. Any suggestions?

The light is a warning for trouble with the braking system, not the brake lights. Check the fluid level.