Dual tanks

[mcssls]

I have dual tanks on a 76 stepside 4x4. When I swith the factory switch the guage is all that changes, there's no sound or hit that it will try to switch. I'm sure I need a new selector valve. Strange part is there's a switch on the door side of the column that someone added. When I hit it it sounds like a dry fuel pump, under the truck whatever this is looks stock. Looks too big for what I think of as an electric pump. Any ideas? Is it original? If so what is it?

[jpoutlaw]

My '77 has the switch on the drivers side down low. It's just a toggle switch but it's original. My gauge changes, no sounds 'cause there's only one fuel pump up front pulling the fuel.

I doubt it's original but someone may have tried another fuel pump at one time. Maybe to help prime the other??? Don't know 100%.

[blink32]

The actual switching mechanism is very small and a bit back from the drivers seat so I wouldn't expect to hear any audible switching in the first place. I've never heard any noise on any of the 3 I've owned with dual tanks. If the gauge readings change then its most likely operating normally.

For the other switch, take a picture and post it? Would help seeing it.

[mcssls]

yeah, I'll have to take a pic tomorrow if I'm feeling human again, right now am feeling pretty ford like.

[boxrodz]

Originally Posted by mcssls

... Strange part is there's a switch on the door side of the column that someone added. When I hit it ...

I thought you were leading up to a 'Stephen Wright'-like joke:
“I have a switch in my apartment that doesn't do anything. Every once in a while I turn it on and off. On and off. On and off. One day I got a call from a woman in France who said "Cut it out!"”

I know the '81 and up have a different selector valve, but I can hear the operation of the solenoid inside the selector valve once I hit the switch. The selector valve changes both the fuel sending unit signal (to the gauge) and fuel pickup between the two tanks. ... interesting that you have another switch.

[79BIG10]

Sounds like what happened to mine. Look for a pink wire at the fuse box that has come loose. This is a power wire to the factory switch that powers it. You're gauge will still move but it won't power the valve.

[mcssls]

got the flu 5 days ago, haven't done anymore than stand on the porch and look at the truck. Maybe I'll get closer this weekend.

[wklink]

My 79 GMC makes no noise when it switches tanks. I know it works because I haven't run out of gas yet