Thanks to chknkatsu over on CumminsForum for this one.
Took me a long to figure out how i wanted to do this without interfering with the everyday use of the truck, that meant not eliminating the spare or taking up bed space. I also wanted two compressors for quick recovery and redundancy in the case of one of the compressors going bad. I also wanted to make sure all the wiring terminations and relays were easily accessible. I sized the wires accordingly to reduce voltage drop.
making a relay/fuse board. It was difficult trying to find a good spot for the relays and fuse that was accessible so i decided to mount it on the fuse box cover with rubber bushings. All the studs are welded onto the board from the backside.
I used the DEF tank mount as my mount for the compressor
because there isnt a flat surface on the DEF tank mount i welded studs onto the mount to mount a plate, all the terminations coming from the engine bay are done in a junction box mounted to the DEF tank mount cover so i can easily access it by removing two bolts and dropping the cover.