I am trying to install a battery isolator to charge both of my batteries, but I am struggling to find a wire that is hot in run only which tells the isolator when to charge both batteries or stop the second battery from being able to drain my main "battery which starts the vehicle". Any advice on what wire/circuit/fuse I should tap into?

 

Welcome to the forum. If no one here can answer then you're probably going to need a copy of the factory service manual which has a wiring diagram in it. I think one or more aftermarket Corvette suppliers also sell just the wiring diagram by itself.