So in a weak moment, I wound up with this little dude (warts and all):



Sadly, I have zero experience with accessory fuel tanks other than the old ones with a mechanical, brass-looking valve/lever apparatus. And also sadly, I found very little help on the internet when "googling" this device. My "new" truck doesn't have "Left and Right" tanks (as the switch implies), it only has the "behind the seat tank" PLUS a later added "between the rails" (between the differential & the rear bumper) accessory tank. The switch as you can see is labeled "Left, Main, and Right" .... ie: 3 positions for only 2 tanks that are actually "front and rear." And just to make it more confusing, someone scratched an "R" over the word "Left" on the switch faceplate. By the looks of the added fuel tank, it's been there a long, long time. So do any of you have experience with this non-factory set up? Or any way (short of running out of gas) to figure out which switch position works which tank, and what is the function of the third setting ("Main")? Thanks in advance! -Lee

Sadly, I have zero experience with accessory fuel tanks other than the old ones with a mechanical, brass-looking valve/lever apparatus. And also sadly, I found very little help on the internet when "googling" this device. My "new" truck doesn't have "Left and Right" tanks (as the switch implies), it only has the "behind the seat tank" PLUS a later added "between the rails" (between the differential & the rear bumper) accessory tank. The switch as you can see is labeled "Left, Main, and Right" .... ie: 3 positions for only 2 tanks that are actually "front and rear." And just to make it more confusing, someone scratched an "R" over the word "Left" on the switch faceplate. By the looks of the added fuel tank, it's been there a long, long time. So do any of you have experience with this non-factory set up? Or any way (short of running out of gas) to figure out which switch position works which tank, and what is the function of the third setting ("Main")? Thanks in advance! -Lee