I installed E-fans on my 2001

[ScottyBoy]

I fought that nut for a good minute then made use of the bar the came with the 36mm wrench. Secured the bar to the pulley with a nut and bolt and added two cheater bars to break the nut free with a two man effort. It was that tight. Stupid tight. No reason to be that tight.

Fan relays were placed to the right of the fuse box where they reside for '05-'06 years. When I pulled the fans from PYP the fuse box was included that has the inspection cover for the relays. It all snapped together easily.

Yeah, it's almost like GM designed that relay block to clip in place alongside the factory fuse block.
And removing the OEM fan clutch is DEFINITELY the worst part of the job. I didn't have a wrench big enough to fit, so I used the biggest pair of Vise-Grip locking pliers that I own and locked them onto the fan nut. Then after much cussing because I couldn't get it to break loose, I then whacked the Vise-Grips with a hammer a few times and that finally broke it loose. After that, it literally spun right off the rest of the way.
As far as the fuse box cover, I've had my relay block sitting underneath my 2001 fuse block cover ever since I installed them back in 2011. I picked up an 05 fuse block cover a while back, but installing it has just never been a priority. I may end up installing it just to get it out of the way.