fuel tank selector

[F2FIDDY]

My truck has a small switch on the dash beside the gauge selector to switch tanks, recently it onlr uses fuel from the Aux. tank, no matter where the switch is set. I don't understand how this switch is supossed to work, does it by-pass the original switch on the floor.
Thanks Doug

[QC]

The switch on the dash only only switches the gas guage from one tank to the other. The valve on the floor swiches tanks.

[FormerMarine1981]

Are you saying that along with the toggle switch to select which tank the fuel gauge reads there is another switch added on that you have been using to select which tank is in use. If so it sounds like a p/o might have added parts from a different year.

[dbarker]

You should have a valve on the floor to switch tanks:

If you had Factory dual tanks you would also get this switch on the dash to select which tank the gauge read from. This SHOULD NOT control where the gas comes from, only what tank you gauge is reading from:

The tank in the cab is your main tank, and under the bed is the aux.

Some trucks had dealer installed saddle tanks. there may have been one or two tanks added. These tanks dont have sending units, so the gauge will not work for them. The valve on the floor is the same, but you wouldnt have the gauge switch on the dash.

If you have something other than this going on, you probably have a hackjob by a previous owner. they may have installed the electronice tank valve from a later model truck and then added a switch to control that valve.

post up pics so we can see what your dealing with.

[Thunderfoot]

if I switch to main tank it will stall and the tank is full, switch back to aux. and shes fine.

Sounds like you have an electric controlled valve for the switching of the tanks and either the valve is not switching all the way over to the Main tank, or the the line from the Main tank to the valve has gotten plugged...
This valve should be under the cab by Drivers door, you should be able to see which lines go to which tanks, try removing the line from the main tank and see if fuel flows (be careful) if it does then it probably is the electric valve that is the problem... You will have to see if you can find any part number on it as this was not a stock factory thing... manual valves were as other said above...

[fordman]

you have to switch both the valve on the floor and the switch on the dash to read and get fuel from the same tank.

[FORDification]

Right....with a factory setup, the floor valve controls fuel flow, the dash switch controls which tank's sending unit is supplying the fuel gauge with a reading.

In other words, you can use fuel from the main tank while reading the fuel level in the auxiliary, if the dash switch is set to "Auxiliary".

[basketcase0302]

"Spierence" as Daryl Waltrip says it!

I've been thinking about switching mine from the manual, (valve beside the door/switch in the dash to switch the gauge). To an electric valve, (I've got the switch and valve from my old 76' Bronco).

But like Keith said, I think the ability to "flip" the switch while driving down the road is like a security blanket. Thinking I like my original set-up like it is.

Basketcase

[1971ford]

hey basketcase,

my PO took out my manual valve thats by the door/seat and installed a button thats on the dash that changes fuel tanks and what tank it reads from. if you want to see me finding out that that is what the button is for, see my topic in the interior section that says "questions about my truck".
my PO also removed the floor hibeams button and installed a switch on the dash. i dont know why though. i can let you know how its set up if you are planning on doing the same thing with the tank switch but i know little on how its set up.
hope this helps.

[F2FIDDY]

How does this electric switch work, or in my case not work. I just ordered the original manual one to get things back to normal, but I would't mind the convenience of a dash switch someday.
Thanks Doug

[basketcase0302]

71' You mean petty officer when you say PO? I'm an old Navy guy. I'm stuck on the old stuff when it comes to our trucks, (I couldn't never figure out why they started putting the dimmer switch on the column anyway).

Old Navy saying...KISS
Keep
It
Simple
Stupid
No implication intended here.
The older I've gotten, (pushin' 50) the easier working on the truck, the better things are!

F2, The electric switch is a "double-pole/double-throw" switch that changes power from one sending unit to the other. The switch also sends power to the selector valve, (a solenoid acuated valve) to switch the tanks.

Hope this helps.

Basketcase