I have been fighting with a squeek above the driver side in my 2008. It is very frustrating! I added the screws like Ron did and they later stripped out. The squeek will come and go, and I enjoy when it's not present. One day it did not make a sound after driving all day, the following day it squeaked. The only difference was that on the second day it was raining. I thought it may be the humidity that caused something (wood) to expand. The third day, another rainy day, and no squeek.
Prior to this evaluation, I believed the squeek was coming from the Romex that feeds the outlet above the passenger side. As bad as it sounds, I shoved a foam pool noodle between the cab (that Ron's screws tap into) and the what net bottom. I think that helped, but it still drives me bonkers when it squeeks!
I am going to see if I can use a thermal Camera to find anything. I drove an inspection camera around and that's where I saw the Romex.