Re: I found this part to be the cause of the erratic climate control fan speed
FWIW, I had this same issue in our 04 Limited, and it was the potentiometer in the controls. However, I did not replace it. I simply used electronics cleaner on it (in it), and then re-lubed it with silicone spray. It has been fine for the last two years, now.
Edit: This took less than an hour with ordinary hand tools to accomplish. Not a major project.