You mentioned that you have voltage out of the switch. Are you sure and did you measure it? If there is definitely voltage out of the switched side(12v) then you probably have an open in the wiring from the switch to the lamps(which may include distribution connector/s).
If there is not 12v on the switched side, then check the hot side of the switch. Is there voltage (12v) on the hot(non switched) side? If not, check at the distribution block for a wire that has either opened up or isn't connected.
If there is voltage on the hot side of the switch but none on the switched side, you have a faulty switch.
Basically what you want to accomplish here is to see where the 12v is missing. Once you have it missing in one section but good in the previous section (working back toward the battery) then the problem is between those 2 points.
I hope that helps in the troubleshooting.
Bob