Re: how to wire this switch
Looking at the back of the switch the pins are numbered 1,2,3,4 on the left side and 5,6,7,8 on the right.
Pins 2 and 6 are connected together with the brass strip. That is +12 volts into the switch. It is NOT related to the internal light.
Pin #7 is the ground connection for the internal light. Pin #8 is the backlight supply IN.
Pins 1 gets powered when the switch is likely in the DOWN position and pin 3 is powered when the switch is in the UP position. Same for pins 5 and 7 on the other side of the switch. That switch will be wired like this for NAVANC lights. You will wire the internal light circuit for the gauges to the same terminal that feeds the bow light. There is no need to have the gauges lit up when the switch is in the ANC position. Consider the terminals on this switch to be 1,2,3 on the left and 5,6,7, on the left Pins 7 and 8 on your switch wee described above.