I think a another maxi fuse is blown.

Something is not allowing the battery voltage to go past the fuse block.

 

I replaced the 175 amp megafuse unless there's more than one

 

What are you working on? and where is the 175 amp. fuse located? I dont think ive ever seen a 175 amp fuse in a pickup.

 

Put your voltmeter on battery and turn the lights on, or try to anyway. What does the voltage do?

 

I'm working on a 2009 gmc sierra denali the 175 maxi fuse is on the fire wall when im in the truck there is zero power no lights ,no instrument cluster, no power to obc2 port, will not click I've charged the battery and it holding charge , tested alternator.
Some people have suggested starter could be doing this but i never had a problem with starter