2004 Chevy Impala fan control

Air Conditioning problem
2004 Chevy Impala 6 cyl Two Wheel Drive Automatic

The interior fan on my Impala, I have to turn it on and wait from 1-5 minutes before it come on. This is very irratating when windows fog up. And every now and then my headlights just go off! I'll pull the dimmer switch lever and they usually come back on. This has happened about 4 times in a year under various conditions.