2007 Kia Sedona seemingly unrelated items not working at th

About 5 days ago I started the van and noticed the a/c fan switch no longer controlled the fan - it was either on high or off. I also noticed the "Air Bag" light is on all the time and the dome lights do not work.

Incidentally, when I started the car that time, I turned the key but didn't hold it long enough for the engine to start, so I turned it again and it started right up, but with these problems. The rear control for the fan in the back of the van is also affected in the same way.

Everything else seems to be working correctly. What could be the problem? And how can I diagnose?

Thanks in advance!