what is this switch for?

Primary tank selection?

 

Exactly.

 

I think it has something to do with pie! LMFAO

 

Always does... ie: which pie in the face you want FIRST?!?!? LOL....

 

Some Petes had two fuel gauges. This switch shows you the level in the tank selected. It doesn't select which tank the fuel gets drawn from.

 

That's not exactly a good idea. That tells me there might be no returns present in either tank circulating fuel to keep both tanks warm in winter. I once lost a tank when the shop mechanic failed to reopen a fuel feed valve for it in the dead of winter, we find out that there is a problem when that tank gelled through and was full. It was a lesson learned the hard way. Never forgotten.

Ive never had to use that kind of switch, but you would cycle that switch several times a day and night to keep your fuel more or less equalized coming down.

 

That switch has nothing to do with where the truck draws fuel from.

You used to have an option to have a fuel gauge for each tank, this just gives a read out of whichever tank it is pointing to on the one gauge

@AlexFromMD next time you are pretty well empty and go to fuel just fill up one side and give the switch a try, then finish filling up, you will see exactly how it works. It is useful to know if your truck is only drawing from one side, think about the threads of freightliners mostly where the complaint is "gauge reads empty but truck ran out and one side is full and other side is empty"

 

You have never used that kind of switch, that explains why you don't know what it does.

 

They have that on airplane... You weren't in a Peterbilt you were in a Cessna... Drunk again