1984 Ranger Diesel with Dual Fuel Tank Issue

[doug1984]

When I bought the truck, the selector switch on the dash was set to the aux rear tank, the fuel gauge worked and so I just used the rear tank. I've left it alone for all these years. My son filled the rear tank with Biodiesel and then a norther blew in so I thought I'd be smart and put some petrodiesel in the main front tank and run on that until the weather warms up. But when I moved the selector to the front tank, the engine died. When I swapped back, the engine would restart, but the fuel guage read Empty no matter where I put the switch. No fuses are blown and the gauge worked before.

Anyone have a wiring diagram on the dual tanks option, selector switch and solenoid valve? Need to know how the gauge works with both tanks? A relay or what.

 

[doug1984]

bump - still no gauge. Truck is running

 

[basketranger]

Question: Do you know why the previous owner did not use both tanks? my guess metal tanks rust, corrosion, trash, is why "they" quit using the primary tank. so would look at the "sending unit(s)" first. (first pull the bed to facilitate access to the tanks) check wiring to sending units then check lines for passage (blow air thru them - need to disconnect from filter so both ends are open to the elements) yes, you will have to bleed the system afterwards. even check the "valve to switch tanks".