no dash lights and gauges on and off
 

I have a 2000 Audi A6 that has been sitting a while. I went and charge the battery (would only charge 50%) and ran rough but after a few minutes it smoothed out. I looked down and there were no lights when I turned the key on, no info display, clock, or odometer. while engine ran,I could see the ABS light come on and one other, an arrow in a circle, but then all the gauges would shut down and go to zero. A few seconds later they would come back on and go off again. The engine is running just fine during all this, headlights, fog lights, interior light all come on, but no dash lights. I bought a new battery and the car starts and run, but the same issues. Help!!!