On my 05 Sportster nothing lights up when the key is on battery and fuses are good what could be the problem It works on occasion.?

It sounds like a bad ignition switch. You should be able to take the switch off and take the wire leads off of the switch. If you touch the positive to negative and everything works correctly, then the switch is bad. Before you do this I would ensure that the power from the battery is getting to the bike so check the terminals.