86 dual tank help

[superwade57]

i have an 86 2wd swb silverado bought it in 2005 with "a blown head gasket" its been parked for years and i finally got around to doing something with it turns out cyl #1 is hatched bad, long story short ive never had the truck running put a good motor in over the weekend and no fuel delivery, it has a clear fuel filter and i can see no fuel is getting to the carb it has a dual tank system and i cant find anythign in chiltons manual about them at all, switch feels funny so i removed it, dont know what wires are what in the dash or if the actual switch on the frame could go bad or how its wired??? im pretty frustrated with this whole situation please save me before my head explodes.

[old Rusty C10]

there is a switch on the dash and a crossover valve above the tanks. If either is bad neither will work. Im sure someone will chime in here with the wiring diagram and the other info for them, but i do know its come up before

[tucsonjwt]

If you really want to get the dual tanks working, you will need that switch on the dash. The dash switch is real inexpensive (less than $20). I would just install the new switch and start from there. Be careful with the switch, because it installs from the front, while you hold the connector from behind the dash with your other hand - it is easy to break the tabs on this flimsy switch. The switch just controls the valve to determine which tank to draw from, so if you have no fuel at all it probably is not just the switch.
If your truck has been sitting for years, you should start by dropping the tanks, inspecting for crud/varnish - cleaning if necessary- then reinstall. Most here prefer removing the truck bed for this task - that will also give you good access to the valve, usually located on the inside of the frame rail (possibly the cross rail). From the valve, the rest is normal hardlines to the fuel pump, then to the carb. If you have an 86 1/2 ton you probably have (or should have) the vapor recovery system with a canister somewhere up towards the front.
It is a good thing that you have no fuel going into your carb, because likely you have so much varnish and junk in your tanks you don't want that in your carb. Your carb also is probably full of crud - worth a cleaning with a can of gumout if you do get clean fuel flowing to it, or you could just drip some fuel down the top of the carb to see if it will fire at all, or have a shot of ether handy.
Good luck.

[superwade57]

thanks guys does anyone know what fuse the dash switch hot is linked to?