Fuel Tank Switch Troubleshooting

[joeymarkgraf]

Hey all, I'm new to the Old School pickup thing. I just got an 81 C-10, which came factory equipped with dual fuel tanks.

I've been scouring the net for 2 days now to find out how the dual tank switching system works, but I have found very little on it.

My problem is that mine doesn't work. I plan on testing the switch with a multimeter to see if it works, but in the mean time I could use a little input on how to troubleshoot this system. It seems like they left it out of my Hayes manual....

Any help or sources of information is greatly appreciated.