Dashboard lights/O2

My wife called this morning saying the dashboard lights are flickering on and off, like house lights in a thunderstorm. Any ideas on what can cause this? Fuse?

Also, I have purchased bank 1 O2 sensor to replace. The check engine light has been for a month and the dealer cames bank 1 is bad. I also purchased the special tools to install it. How hard is it to install? Any time frame? I have installed them in a 2000 dodge intrepid before.

I forgot to tell you guys it is a 2001 Jetta. Please respond. I need some input.

For the lights I'd try jigling the headlight & dimmer switches to see if they might be causing the trouble. The O2 isn't harder than any other, the wire can be a pain to get clipped back in properly.

Thanks, the headlights are working properly. I saw that the wire goes under the firewall and figured it would be a pain.

You can reach 2.0 o2 sensor from above but you need to remove the black plastic cover for the wires and unplug it and unclip it from he heatshield.

So you dont think I will need to jack up one side to get to the connection to unplug it? I'm going to attempt to fix it tonight. I got the part and special tool kit to do it so am hoping it doesnt take too long. Anyone else have any suggestions on replacing the bank 1 O2 sensor?