swittch on driver side floor

[dark7068]

what is that toggle switch for?? theres no sticker or anything to let me know, thanx

if you need a picture, I can take one tomorrow

[FORDification]

Does it look something like this, except without the top plate?



If so, it's the fuel tank selector valve, used when an auxliary fuel tank is being used. It allows you to select which tank to draw fuel from. It's just a manual valve which has no effect on the fuel gauge. Later versions of this switch also had an electrical switch which fed current from the sending unit to the gauge so the gauge would read from the tank being used. However, on our older trucks, there was another switch mounted up under the dash to select which fuel tank the gauge was supposed to read. It looked like this:



When switching fuel tanks, you'd have to first hit the valve on the floor to select the tank, and then hit the switch under the dash so the gauge would read correctly.

[dark7068]

thanx alot. thats them alright. I filled my tank up the other day, have both to main, and it reads 1/4 full. Guess I have some work to do

Rick

[FORDification]

So what does the other tank read? Since you just filled it and therefore it should read full, it's always possible the lines going to the valve got switched by a previous owner, so when the switch is on Main it's actually on Auxiliary (and vice versa).

[dark7068]

I;ll check tomorrow and let you know, thanx

rick

[dark7068]

heres my switch. where should the lever be??? for the main tank.

Rick

[Jimbo]

I am having the same problem. Mine is a 69 F-100 custom cab. My switchis on the dash and looks like a togle switch. It say Left-Main-Right and only my right one works a little. I will be checking back to see if you come up with anything. I need a wire diagram to see if it is wired right.

[cancow]

[quote="FORDification"]Does it look something like this, except without the top plate?


Do you have a different top plate? Why a main, left and right? Mine has a Main and an Aux. and an off i think. Then someone painted an 'I' 'E' and an 'F' on it for some reason.

[FORDification]

The picture above is from a truck equipped with dual auxiliary tanks, one on each side, PLUS the one in the cab. If you've only got one auxiliary tank, then you'd have a different valve and top plate. (Or maybe even the valve is the same, with the extra line plugged).

[cancow]

Since my aux tank has not been used in 10 years or more it sounds, should i do anything to it besides run some new fuel throught it before using it?

[FORDification]

I think if it were me, I'd spend a day and drop the tank out and get it flushed. If there's fuel in there, it's going to be bad, plus you could very likely have some rust/gunk/etc in that tank. If the gas cap was doing it's job and sealing the tank, you could luck out and have a clean tank....but if the gasket wasn't up to snuff, moisture could have entered the tank and started rust. It would eliminate the possibility of problems down the road, and give you peace of mind. Of course, it IS going to be a PIA, but it's a labor of love, right?

[greasemonkey060]

Dark, i had the same problem, couldn't read the badge to tell which way was which..

with gas prices the way they are, i swapped the lines so the in cab tank goes straight the the fuel pump. no confusion!