I have a 1970 camper special with the second gas tank but since before I owned it the saddle tank was disconnected and I have not had time to care about getting it working; I assume it's full of rust. Some day.

In the meantime the fuel gauge stopped working for the main tank. Finally narrowed it down to the dash switch being bad and for the time being put a jumper wire and all is right with the world. Here's my question though. Where do all the other wires go to that switch? I can't find a decent schematic that zeros in on that and considering the tank selector valve is manual and the fuel pump is mechanical what to the other 5-6 wires do?

THX

 

I recently had that wire bundle unwrapped for a visual inspection.
The three black wires don't go anywhere.
For the three other wires, one goes to the Instrument Cluster, and the other two come from the tank senders.
The switch is six pins, acting as two single-pole, double throw switches ganged together. Half of each switch (one 'gang' or the other) is unused.
The wiring diagram for the switch looks like this:

The wires on the left would head to the Instrument Cluster, and the ones on the right would come from the tank senders. Which half gets unused? It doesn't matter.

It might be possible, depending on how the switch failed, to use the 'other half" as a temporary repair. I don't think I'd rely on that.

Swapping out the switch should be a fairly inexpensive repair, but good luck on finding a Ford replacement. You may be better off to find a switch that functions the same, has a footprint that is "close enough" to mount in your dash, and a wiring connector/pig tail that fits the pins on the back of the switch, so you can splice into the existing wires. That should save you a lot of time looking for the exact replacement.

 

good info. Thanks

I found a couple places online that claim to have the switch but they want stupid money for them. Double throw generic switch isn't hard to find but might be years before I get the other tank cleaned anyway.

I took the switch apart and it was a mass of corrosion.

Funny that some of the wires go no place. The switch in my E350 van controls the gauges and electric fuel pumps for each tank and I think it has less connections.

cheers

 

https://fordification.com/tech/wiring/68-32.jpg
https://fordification.com/tech/schematics_h.htm

 

D3TZ-9A050-B (replaced C1TZ-9A050-A) .. Selector Switch-Use with Dual Fuel Tanks / Available from Ford

1967/72 F100/350 // 1961/89 C700/900 // 1970/89 LN600/900 // 1975/85 E100/350.

MSRP: $57.27 / autonationfordwhitebearlake.com online price: $34.65.

 

thx.

your diagram confirms what was mentioned above, there are only three wires to the switch. I guess it must have been provisioned for some optional use or different application

 

Ganged switches are used to operate two (or more) circuits at the same time, where the circuits cannot or should not be intermixed.
One application might be for a low-voltage pilot light that needs to operate at the same time as a high-voltage oven.
In the case of these trucks, I think it's probably a residual issue from the previous implementation of electric fuel pumps on some of the larger trucks. With the switch set to "Main", the "main" gauge would indicate the remaining fuel and the "main" fuel pump would provide fuel to the engine. Because we have a manual fuel selector valve, the wiring for the electric fuel pumps became obsolete (at least for our trucks).

GC has a SPDT Ganged switch for under $5. I don't know if the footprint is close enough for the dash, and since it has screw terminals, there wouldn't be a connector or pig-tail to mate with it.

 

Here is the replacement aux tank that I used. It came with the sending unit.


Model #


Position of vent tube was only difference

 

GaryKip We have that one in stock. I am contemplating picking it up for mine. How easy was/is your removal/installation?