Don't get hung up on the nothing has changed.You could end up wasting a lot of time assuming it's all good.
Start at square one and work your way though all the connections from the battery's to the starter.
Last month i helped a fellow out that has electrical issues with a truck he uses to haul water.It gets used once a week and has a drain that kills the battery by the time he needs to use it again.I recommended he install a battery disconnect,but in the meantime to keep from freezing his battery i showed him how to disconnect the ground.
A couple of weeks pass and he gives me a call that there is something wrong with his starter now.He had hooked up the battery and had nothing,put a charger on the battery and still nothing.
He is a science teacher who also has a trap-line that gets him 100's on miles from home.He begged me to fix his truck,my shop is closed so i don't fix other peoples stuff right now.He helped me when i was reconditioning some cast iron rads,so i told him i would look at it.Turns out that someone had loosened the positive on the battery and never tightened it.He swears he never touched it,but it was loose and an easy fix that a fresh pair of eyes found.He spent hours looking for loose connections,crossing the terminals on the starter,ect.
I spent less than 5 min to get the truck running.
So don't get hung up on "nothing has changed" because something has or your truck would be running.
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews