Hardwire Cigarette Lighter

[Viper5]

My service manual says e6 is 7.5 amps and controls navigation, orvr, and terminal 30 telephone. I know what you mean by the refueling (orvr), but how do you know which terminal it is? For instance, e8 is also 7.5 amps and controls navigation and terminal 15 telephone. And can I replace the square 7.5 amp fuse with one from the store or do I have to get it from a dealership.