The switch power one dual tank gauge and those are a yellow wire with one tank only providing the signal. They pull simultaneously and are close in draw, though slightly balanced to either side due to the anti-siphon valve in the pickups. The wire should have a signal to the dash from the wire color on the 10 gallon tank sender, and it goes straight to the dash assembly, which the switches between the chosen tank signals. Left is the under seat tank, and right is the rear tank levels.
You have an amazing ride and we hope you respect the potential and enjoy it.