I can see what that picture says.

Here's something to ponder. You apply power with the switch, to the solenoid, to switch tanks. Wouldn't it make sense that the default tank would be the main tank? Mine defaults to the midship tank. When you flip the switch and apply power, it switches to the rear tank.

Not only that, but on every switch I've ever seen, the **** points to the function you're using... Think of it as an off/on light switch, the **** points to off when the light is off, it points to on when the light is on. If it points to main it should be using main, if it points to aux it should be using aux.

I don't know what you're thinking dennis, but your **** is pointing to "main" and you say it's sucking on the midship tank.... That seems to confirm my point.

I think most people would assume that, rather than think that it shut's off that tank.

 

Basically, I think fords definition of "main tank" changes depending on which tank setup you have...

That picture doesn't even say "main" it just says standard (which that is the standard tank) and auxilliary.

If one tank become main, then the other would have to change to auxiliary

 

Main Fuel Tanks were mounted in the center of the vehicle for weight distribution.

The AUX tank was meant at an added tank.. the Mid-ship position allows for added fuel capacity.

I take the switch when leaving the printed position on the dash as "opening that tank to allow fuel to run"

I'm pretty sure most of the Ford parts books refer to that rear tank as Main .

 

1973 thru today: Correct Ford nomenclature: The rear tank is AFT AXLE / front tank is MID-SHIP.

After 1972: Ford did not refer to any fuel tank as an auxillary. The "auxillary" term refered to the 25 gallon optional underbed tank offered 1967/72.

Consider: On some 2WD** and 4WD F100/350's, Ford did not offer a MID-SHIP tank, so what does that do to y'alls theory that the MID-SHIP tank is the main tank?

When the 1973 models were introduced, the AFT AXLE tank was standard equipment, the MID-SHIP tank was optional.

So, when you get right down to it, the AFT AXLE tank is the main tank.

** Seeing is believing: Look up a fuel tank for a 1974/76 Super Camper Special, you'll see > > D3TZ-9002-V / 20 gallon _______ plastic (fill in the blank with what Ford sez).

 

This might be of some interest to some.
Page 9, 2nd paragraph
1978 Ford Truck owners manual

 

Dueling references.

The Ford truck parts catalogs only list AFT AXLE or MID-SHIP tanks after 1972.

There is no mention of the term auxillary in parts catalogs after 1972.

The owners manual shows both tanks, but the MID-SHIP tank was originally an option, and was not available on some others like 1974/76 Super Camper Specials and some 4WD's.

 

Not trying to fuel the fire of the Debate here but... My 78 F250 4x4 is also labeled on the dash as having the Mid-ship tank as Main. I have only had the truck about 5 years so is it original your guess is as good as mine. But the truck is very original. Just saying there could have been a few that slipped down the assmbly line with a few wires swapped.

JON

 

Wow. I think it's time to lay this one to rest guys... (again.)

Pretty cool to see Ford documentation supporting both theories tho...

 

That's why I said Dennis was only right part of the time on this one. It seems that there are 1978 f250 4x4 trucks out there where the midship tank is considered the main tank, both on the truck and in the owners manual.

My truck is one such example. To me at least, this seems to prove that ford didn't stick to one standard. Standards changed depending on the truck...

 

Sorry for double posting, but I felt I needed to say this.

Dennis, your fuel switch and tank setup seems to be the same as mine. Yet, it seems to me at least that you are reversing your thinking to make the switch operation conform to what you think is the only standard (aux being mid, and rear being main)

Let me try to clear that up some, it's easy to understand, hard to explain. And I don't mean to offend you dennis, don't take this that way...

Dennis believes that there is one standard when it comes to these fuel tanks. He thinks that the rear tank is always the main tank, and the midship tank is always auxiliary.

So when he got his truck, and the fuel switch does the exact opposite of what he expects, he alters his perception of what the switch is doing in order to have the truck conform to the standard that he considers "set in stone".

Most people I think would agree that a switch's **** usually points to the condition that is currently set. Apparently dennis thinks his truck's switch operates differently...

Once again dennis, no offense intended...

 

Dude...what part of drop it did you not understand?

 

No offence taken.

If you read the text under the rectangular box with the switch in it.. it says right there.
when the switch is located in the AUX tank ( Midship) position it pulls fuel from the main tank .

which is what I stated is my point.. it pulls fuel from the opposite position of the switch location.

It is th position of the switch that is being misconscrued

The switch on the heater switch only mounts one way.. any differences would be from the wiring on the solenoid tank switch being wrong but, they are colour coded so a mis-connection is unlikely.

 

I re-read that 3 times and it tells me the exact opposite.

Qouted from manual picture, shortened some: "The valve is energised when the switch is moved FROM main position TO aux position, allowing fuel flow from aux tank"

It goes on to say "on trucks with dual tanks, the MAIN position draws fuel from the midship tank"

I think you might be misreading that...

 

here's a 'for instance'....say for whatever reason, you wanted to reverse the setup so that it's 'backward'....that should be as simple as changing wiring leads at the switch....and maybe that was done, either on purpose, or, as suggested, perhaps inadvertently during repairs...

i'm in agreement with the rear being main....on a styleside, the rear is standard equipment, hence the appellation 'standard' as above....the 'aux' is optional and comes with a 2nd filler toward the front of the bedside....there was no option for ordering the 'aux' w/o the 'standard'.....

thus in no case would it be the 'main' tank, from the factory, even though i think it holds more fuel

 

In the 1978 f series owners manual (in the picture above) it states that the main position of the switch pulls fuel from the midship tank. Would that not mean that on those particular trucks, the midship tank is considered the main tank?