Backwards Fuel Selector Switch
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Senior User
Joined: May 2014
Posts: 463
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From: Ashton, MD.
Backwards Fuel Selector Switch
Ok while i work on that other issue here's another that really bothers me that I'd love to work out... basically my fuel selector switch is backwards. Stay with me on this explanation.
-My REAR tank is operational, however the FRONT tank is gone.
-My Tank Selector Switch must be on FRONT for the truck to run.
-Gas gauge works but shows E at all times when selector is on FRONT.
IF....
-I switch the selector to REAR, the truck will stall out and not run.
-Gas gauge will show the current level for the REAR Tank. (Needle moves up)
I understand whats going on here as you probably do, but would like to straighten it out so switch is on REAR, pumps fuel from tank, and shows current level on the gauge. In conclusion, the only way to see how much fuel is remaining is the switch the selector to the rear, and then switch it back to the front before it stalls out. All this going on when there is no front tank and only a rear. Confused yet?
-My REAR tank is operational, however the FRONT tank is gone.
-My Tank Selector Switch must be on FRONT for the truck to run.
-Gas gauge works but shows E at all times when selector is on FRONT.
IF....
-I switch the selector to REAR, the truck will stall out and not run.
-Gas gauge will show the current level for the REAR Tank. (Needle moves up)
I understand whats going on here as you probably do, but would like to straighten it out so switch is on REAR, pumps fuel from tank, and shows current level on the gauge. In conclusion, the only way to see how much fuel is remaining is the switch the selector to the rear, and then switch it back to the front before it stalls out. All this going on when there is no front tank and only a rear. Confused yet?
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Do you have electric in tank pumps?
The switching valve mounted on the frame how many ports does it have?
Has any of the wiring to the valve been hacked with like when the valve is replaced and the plug is different?
Is the valve marked "F" & "R" and if so where do the hoses go to?
I ask because my 3 port valve for my 81 F100 was marked "F" & "R" and I can hook either tank to the ports so the rear tank can go to the "F" port.
Dave ----
The switching valve mounted on the frame how many ports does it have?
Has any of the wiring to the valve been hacked with like when the valve is replaced and the plug is different?
Is the valve marked "F" & "R" and if so where do the hoses go to?
I ask because my 3 port valve for my 81 F100 was marked "F" & "R" and I can hook either tank to the ports so the rear tank can go to the "F" port.
Dave ----
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Senior User
Joined: May 2014
Posts: 463
Likes: 2
From: Ashton, MD.
Do you have electric in tank pumps?
The switching valve mounted on the frame how many ports does it have?
Has any of the wiring to the valve been hacked with like when the valve is replaced and the plug is different?
Is the valve marked "F" & "R" and if so where do the hoses go to?
I ask because my 3 port valve for my 81 F100 was marked "F" & "R" and I can hook either tank to the ports so the rear tank can go to the "F" port.
Dave ----
The switching valve mounted on the frame how many ports does it have?
Has any of the wiring to the valve been hacked with like when the valve is replaced and the plug is different?
Is the valve marked "F" & "R" and if so where do the hoses go to?
I ask because my 3 port valve for my 81 F100 was marked "F" & "R" and I can hook either tank to the ports so the rear tank can go to the "F" port.
Dave ----
The tank selector valve has no fuel lines on it. So I guess it’s bypassed.
However there are wires still connected. That being said I see a black wire running from the fuel tank all the way up to a bundle of wires on the drivers side fender under the hood it’s spliced in with what looks to be a brown wire with white stripe. I don’t care as much about where the tank switch is as much as I’d like to be able to see my fuel level on the gauge.
Cargo Master
Joined: Jan 2019
Posts: 3,369
Likes: 16
From: Caraway, AR
Are you going to put a midship tank back in it, or has it been upgraded to the 38 gallon rear? If you're not planning on putting the second tank back in it, I'd be guilty of wiring the pump and sender direct, cutting the switch out completely. Then again, I've considered putting the 38 gallon rear in my truck and using the midship tank(no plumbed to the engine) as a holding/transportation tank for other fuels, like say, diesel for use around the farm, or non ethanol gas. Would keep you from needing to haul fuel jugs around, just need a cheap fuel pump and a bit of hose. And if you wire your set up direct and don't use the switch, you could have some fun and wire the ignition through it, that way it has to be set on say rear tank, or the truck wont start, like anti theft and what not.
Thread Starter
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Senior User
Joined: May 2014
Posts: 463
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From: Ashton, MD.
Are you going to put a midship tank back in it, or has it been upgraded to the 38 gallon rear? If you're not planning on putting the second tank back in it, I'd be guilty of wiring the pump and sender direct, cutting the switch out completely. Then again, I've considered putting the 38 gallon rear in my truck and using the midship tank(no plumbed to the engine) as a holding/transportation tank for other fuels, like say, diesel for use around the farm, or non ethanol gas. Would keep you from needing to haul fuel jugs around, just need a cheap fuel pump and a bit of hose. And if you wire your set up direct and don't use the switch, you could have some fun and wire the ignition through it, that way it has to be set on say rear tank, or the truck wont start, like anti theft and what not.
All i I really want is for my gas gauge to function. Don’t really care alll that much about the selector switch.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
The fuel tank selector switch is located in the heater panel, it switches the tanks and the dash fuel gauge from one tank to the other.
D5TZ-9A050-A .. Fuel Tank Selector Switch - 5 terminals - Use with single fuel system / Marked: D5TB-9A050-AA / Obsolete
1975/86 F100/350.
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E3TZ-9A050-AA.. Fuel Tank Selector Switch / Marked: E3TB-9A050-AA / Obsolete
1985 F150/350 with dual fuel line system // 1983/86 F250/350 with 6.9L Diesel // 1983/86 F250/350 460 with electric fuel pump.
D5TZ-9A050-A .. Fuel Tank Selector Switch - 5 terminals - Use with single fuel system / Marked: D5TB-9A050-AA / Obsolete
1975/86 F100/350.
---------------------
E3TZ-9A050-AA.. Fuel Tank Selector Switch / Marked: E3TB-9A050-AA / Obsolete
1985 F150/350 with dual fuel line system // 1983/86 F250/350 with 6.9L Diesel // 1983/86 F250/350 460 with electric fuel pump.
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Thread Starter
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Senior User
Joined: May 2014
Posts: 463
Likes: 2
From: Ashton, MD.
The fuel tank selector switch is located in the heater panel, it switches the tanks and the dash fuel gauge from one tank to the other.
D5TZ-9A050-A .. Fuel Tank Selector Switch - 5 terminals - Use with single fuel system / Marked: D5TB-9A050-AA / Obsolete
1975/86 F100/350.
---------------------
E3TZ-9A050-AA.. Fuel Tank Selector Switch / Marked: E3TB-9A050-AA / Obsolete
1985 F150/350 with dual fuel line system // 1983/86 F250/350 with 6.9L Diesel // 1983/86 F250/350 460 with electric fuel pump.
D5TZ-9A050-A .. Fuel Tank Selector Switch - 5 terminals - Use with single fuel system / Marked: D5TB-9A050-AA / Obsolete
1975/86 F100/350.
---------------------
E3TZ-9A050-AA.. Fuel Tank Selector Switch / Marked: E3TB-9A050-AA / Obsolete
1985 F150/350 with dual fuel line system // 1983/86 F250/350 with 6.9L Diesel // 1983/86 F250/350 460 with electric fuel pump.
There is a black wire running straight from the back tank all the way to the drivers side fender where it’s spliced into a brown wire with white strip. I was hoping they just spliced into the wrong wire and someone might know the right one to splice into.
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Cargo Master
Joined: Jan 2019
Posts: 3,369
Likes: 16
From: Caraway, AR
Thanks for the info but I don’t think my switch is malfunctioning, I think the prev owner screwed something up when getting rid of the front tank and possibly replacing the rear and electric fuel pump.
There is a black wire running straight from the back tank all the way to the drivers side fender where it’s spliced into a brown wire with white strip. I was hoping they just spliced into the wrong wire and someone might know the right one to splice into.
There is a black wire running straight from the back tank all the way to the drivers side fender where it’s spliced into a brown wire with white strip. I was hoping they just spliced into the wrong wire and someone might know the right one to splice into.
Thread Starter
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Senior User
Joined: May 2014
Posts: 463
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From: Ashton, MD.
I pulled it out yesterday... there’s an orange wire, pink, brown, and black. My guess was the wire coming from the tank was spliced into the brown one on the fender.
Cargo Master
Joined: Jan 2019
Posts: 3,369
Likes: 16
From: Caraway, AR
Give me a couple hours to get back to my computer and what diagrams I do have and I'll see if I can explain what I'm thinking.
Thread Starter
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Senior User
Joined: May 2014
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From: Ashton, MD.
Thanks! By the way the innova 5568 is sweet!
Cargo Master
Joined: Jan 2019
Posts: 3,369
Likes: 16
From: Caraway, AR
Im having a hard time seeing what all wires/ colors are here. Is there another brown/white stripe here? If not can I get you to post another picture showing the backside and all the wires going in?
Cargo Master
Joined: Jan 2019
Posts: 3,369
Likes: 16
From: Caraway, AR
Even better, set it to rear tank on the selector switch, turn key on, and pierce that red wire with your volt meter. I've been guilty of opening a safety pin, wrapping it around the hot lead on my meter and taping it in place and using that to probe or pierce. Put the black on any ground and see if you have voltage. If you do, and I can't be positive, all the diagrams have been kind of a mess. But I'm thinking if it's hot with the switch on rear(that is the one the sending unit works on?) then you can take that black wire connected to the brown/w and splice it into the red. Assuming I'm reading these diagrams right, the rear setting makes the gauge work, and the red wire is hot when the switch is on rear.
Thread Starter
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Senior User
Joined: May 2014
Posts: 463
Likes: 2
From: Ashton, MD.
Even better, set it to rear tank on the selector switch, turn key on, and pierce that red wire with your volt meter. I've been guilty of opening a safety pin, wrapping it around the hot lead on my meter and taping it in place and using that to probe or pierce. Put the black on any ground and see if you have voltage. If you do, and I can't be positive, all the diagrams have been kind of a mess. But I'm thinking if it's hot with the switch on rear(that is the one the sending unit works on?) then you can take that black wire connected to the brown/w and splice it into the red. Assuming I'm reading these diagrams right, the rear setting makes the gauge work, and the red wire is hot when the switch is on rear.
That's the thing that I'm having a hard time making sense of. The only wire running from the rear tank to the front fender is the black wire. Couldn't that just as easily be the power supply to the electric fuel pump in the tank?