Hy buddha, Its always interesting trying to do diagnosis by braille and long distance. Flickering lights, bad power connection at light switch or at feed source to light switch. Tail lights burning out fuse, I assume the fuse is adequate for the circuit, are there any other lights that are on with the tail lights, parking lights? We must isolate the circuit in question, Obviously the tailights are not shorted to ground at the bulb holders because your brake lights/turn signals work okay. How old is your light switch, the flickering could be a bad connection to the switch,or a bad connection through the switch, bad connections cause heat which causes resistance which raises amperage which may cause your fuse to blow, other than that the tail light wire may haved chaffed through somewhere on the way to the tail lights
