Fuel selector plug voltages

[Ronw435]

Just pulled my front and back tank and cleaned the fuel hat debris from each tank and cleaned them out. Going to try to get the FSV working but would like to know the voltages at the plug when switching from front to back.
I checked the plug with the front tank selected and I get an intermittent voltage at only one wire.( the second from the end) It shows voltage for about a half a second then nothing then voltage for half a second. When I switch to rear tank no voltage anywhere.

Does anyone have a schematic of the wires with the proper voltages at the wires?

Thanks
Ron

 

[Cubey]

It's supposed to be 12V on the two power wires. The other 3 are the sending units and gauge.

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[Ronw435]

Thanks Cubey

Do you know if there is a solenoid involved with the switch?

 

[Cubey]

Thanks Cubey

Do you know if there is a solenoid involved with the switch?

No solenoid. The power comes from the fuse panel somewhere, goes to the switch, then goes to the valve.

Here is what a diagram looks like to install one on a vehicle that never had one. Same exact wiring, just slightly different pinouts because it's not the Ford factory connector:

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[Ronw435]

Do the FSV ground to the frame? Or is it done through the wiring?

 

[Cubey]

Do the FSV ground to the frame? Or is it done through the wiring?

Wiring. the two power wires are reversed back and forth polarity wise

Look back up at the first post of diagrams I posted, the second diagram has the "valve electrical table".

Set to front tank: wire #1 is negative, wire #2 is positive

Set to rear tank: wire #1 is positive, wire #2 is negative.

 

[Ronw435]

Thanks Cubey

 

[Ronw435]

Ok new selector valve but still no rear tank. Are there solenoids involved in the wiring?

 

[Old Goat]

No solenoids that I have seen or noticed in the schematics.
Your rear sender may not be working?

Ea tank has one wire that goes into the connector that plugs into the FSV.
Pin#5 rear tank, yellow/blue stripe
Pin#4 goes to the Gauge Yellow/white stripe
Pin#3 Front tank Blue/Yellow stripe

When you flip the switch on the dash do you hear the FSV make any noise, click, humm etc...?

There is a little motor in the rear of the FSV that connects the contacts 5 to 4, or 3 to 4 for the gauge to work on the correct tank.

There is 2 valves it also pushes or closes for the correct tank.
I have 3 of these I have taken apart to see how they work, one is a genuine Ford FSV, Ford in the plastic housing along with pollack, and a China made little electric motor.

Back half is the motor and a PC Board with the 5 copper contacts for the 5 pins of the plug connector. Front half is the 6 nipples for the fuel lines and the 2 valves for the correct supply/return for ea tank.

Number Dummy a retired Ford parts guy, said these FSV`s were junk from the beginning.
he is on the this Forum or maybe on FTE Forum.
very knowlegabel (that a word?) guy when it comes to Ford parts.

I got so frustrated with mine, I finally ripped it out and ran the rear tank to the engine and back, and have a 38 gal tank.


Goat

 

[Cubey]

Maybe one of the two power wire is damaged somewhere along the way? You can run new wires. Refer to the schematics above if you want to end up doing that, it tells you how to do the wiring.

 

[Ronw435]

Thanks Goat, I hear nothing when i flip to the back tank. On my selector switch i have the red wire on only one side. The orange is adjacent next to the red, brown below the orange, and black on the bottom under the orange. I had the selector switch apart and I cannot understand how the red wire gets to anything. I have looked at some of the other switches on the ******* page which show the red connects to the opposite diagonal corner. Cannot see how the red can get to that location on the switch?? I know that the red and black reverse polarity but I can not for the life of me understand how the red can get to negative? Am I correct on the fact that there are only 4 wires on the selector switch which has 6 wire lugs on it where the plug goes into it? Sorry to be a pain with this but im about to set the truck on fire.......lol. Well not really but this is sure frustrating.

 

[Cubey]

Thanks Goat, I hear nothing when i flip to the back tank. On my selector switch i have the red wire on only one side. The orange is adjacent next to the red, brown below the orange, and black on the bottom under the orange. I had the selector switch apart and I cannot understand how the red wire gets to anything. I have looked at some of the other switches on the ******* page which show the red connects to the opposite diagonal corner. Cannot see how the red can get to that location on the switch?? I know that the red and black reverse polarity but I can not for the life of me understand how the red can get to negative? Am I correct on the fact that there are only 4 wires on the selector switch which has 6 wire lugs on it where the plug goes into it? Sorry to be a pain with this but im about to set the truck on fire.......lol. Well not really but this is sure frustrating.

Again, the wires get criss crossed at the switch in the cab. What number is your red wire?

4 wires go into the switch because that's power. You have 5 at the valve because 2 are power, 1 is the gauge, and 2 are the sending units. Only 2 wires are coming from the switch going to the valve. The gauge and sender wires do not go through the switch, the valve deals with that circuit.

 

[Ronw435]

Cubey here is a pic of the back of the selector switch showing the wires. If you have ever taken the switch apart I don't see any way for the red wire to connect to any other wire in the plug. The red does not cross over in the switch like a dpdt switch does in your pic. The red would connect to the other terminals that do not have anything on them. Not sure if one has pulled out but i cannot find any loose connectors.

 

[Cubey]

Cubey here is a pic of the back of the selector switch showing the wires. If you have ever taken the switch apart I don't see any way for the red wire to connect to any other wire in the plug. The red does not cross over in the switch like a dpdt switch does in your pic. The red would connect to the other terminals that do not have anything on them. Not sure if one has pulled out but i cannot find any loose connectors.

Again, look at the second diagram I posted at the link below. It shows that connector and where that wire goes. It also tells you how that wire connects in the switch.

Fuel selector plug voltages

Just pulled my front and back tank and cleaned the fuel hat debris from each tank and cleaned them out. Going to try to get the FSV working but would like to know the voltages at the plug when switching from front to back. I checked the plug with the front tank selected and I get an...

www.oilburners.net

 

[Ronw435]

Cubey, I appreciate your patients with me. I am sending a poor drawing, lol, of how the switch is on the inside. There are two copper bars that are meant to connect two terminals together at the same time. The switch moves a plastic block that has the bars on it with springs to keep it connected. The bars (contact surfaces) only go up and down. The red wire is connected to one side the orange, brn, and black at on the other side. I cannot see any way the red wire can come into contact with any other terminal. They do not cross over like the DPDT switch indicates. I hope the diagram i drew makes sense.