Just bought a 79 250 with dual fuel tanks. I can not find the switch to switch bewteen my two fuel tanks. Where are typically located? Also is it a labeled switch or something simple just like a small toggle? Thanks for the help.

 

To the right of the HVAC control panel, assuming they're factory installed dual tanks.
BTW, welcome to FTE. Lots of good people here.

 

Thanks alot for that, follow up question. Which tank is considered the main and which is considered the aux?

 

Main tank is usually the aft axle tank and the side tank the auxiliary.

 

Welcome to FTE as well. BTW post pics