my 16 ram truck needs a 125a fuse. after replacing does the truck need to be reprogrammed?
My crystal ball says it’s the one for the power steering by the battery. 
I would disconnect the battery before installing it. you should be ok after that. but others here might know better.
I want to know what/how a 125 amp fuse was blown??..
But with the battery cable disconnected as mentioned above, replace fuse and connect the battery and see what happens…