Michael Elijah Dyson

So I've had an issue with my 2006 Jeep Grand Cherokee Laredo for just a few months where every now and then my lights will flicker. I've done a decent amount of research and read that it could be my headlight switch, I've purchased a new one from Autozone and know how to change it out but before I did I wanted to ask a few questions.
1. Is this likely the correct fix? The symptoms are as mentioned above, headlights flicker as well as dash lights and only once it happened as I was getting out of my car and all of the lights inside flickered.
2. I've read that taking out the existing switch and sanding/ cleaning it up a bit will likely yield the same results. Any insights on this would be helpful as well and potentially save a bit of money.
3. Not very long ago my ABS, ESP BAS, and traction control lights came on. Nothing happened (that I am aware of) they just were on one day and didn't go off. I'm not sure what could cause this/ if there are any ways I could do anything about it at home. I'm not against just taking it into the shop but I'm interested in learning more about my car and taking care of it. I also wasn't sure if this could have been caused by some sort of electrical issue which could also be the cause for the lights.

Thank you in advanced for any help and I'll do my best to answer any additional questions.

LIL Crabby

I was just passing by when I saw your post. If this was my car, I would check all my ground wires. It sounds like a loose/dirty ground connection to me. Worth checking out anyway as an preventative maintenance thing. I was thinking 'switch' until you mentioned the other stuff had blinked on and off. Start with the ground connections.