Audi A3 instrument box problems

Good afternoon,

I need help solving a small problem with my A3. It all started in the summer when the battery died and I had to replace it. Before that, the instrument cluster light would sometimes illuminate more or less brightly with the car running; that is, the intensity of the light would vary, and it wasn't due to changes in daylight. This went on for a while until one day the digital display in the instrument cluster stopped working altogether. It wouldn't turn on. I started investigating, and by removing fuse 17 from the fuse box on the left side of the engine compartment, the display came back on when I started the car. When I turn the car off and try to start it again, the warning light doesn't come on.
I drive the car every day to work, and one day I left it in the garage for a couple of days—surprise!—battery dead! This has happened a couple of times now, and I've noticed that the warning light stays on all day. I'm hoping

someone can help me out. Audi told me I need a new instrument cluster to fix the problem with the warning light—€800 for the whole thing.