oh ok, so yours has a boot. just trace that orange/red wire to its end. and plug it into the two green wires boot. that should fix your gauge problem, if the gauge and unit are still in working order.

 

ok so went back to my truck and followed the wire that came from my fuel tank too the dash.from the picture you can see, the arrow without txt from what i was able to follow is the same wire from the fuel tank after it goes through elctrical tape.



however it is cut here.


now what i am wondering now is the green/yellow wires are supposed to be fuse to courtesy lamp switch, what would happen if i was to connect the cut wire with the two green/yellow to single red wire? dont want to melt or start a fire

 

what i would do is splice both cut ends together, orange to orange. you could hit one of the green wires, but if you ever need to disconnect you can just unplug the boot if you stick with the orange. i would take a pair of crimps or something you can crimp with and use a connector to put the two red/orange wire ends together.

 

no worries, if it helps people out :-)
ref your pic, my orange wire goes up & over the door frame then comes out under the dash and goes into the fuse box, just before the fuse it splits & goes to the gauge selector switch, on my truck it sits under the dash below the headlight switch & ignition switch, hope that helps you out..

 

thanks Darrell, just shows to try the simple things first and not try to over complicate things :-)

 

well.... i unraveled some of the electrical tape that the cut wire was hanging out of, unfortunately that wire just goes outside, which leads me to believe my sending unit maybe outta wack. and i tracked the fuel wire all the way to the gauge it doesn't go to the fuse box.

 

so the sending unit wire is hooked straight to the gauge? if thats the case, the easiest thing to check is the sending unit first. take it out of the tank and disconnect the wires. if you put an ohm meter to it it should read around 73 ohms empty and around 7-10 ohms when full. if you get these readings then your sending unit is good and your gauge is shot. imho i would just get an after market gauge and cup from autometer, 73-10 ohm, and put that in your truck. my gauge didn't work and i could not for the life of me find anyway to replace the original gauge without replacing the entire instrument panel, which was a lot more money and time than just getting a $43 dollar gauge and is a very easy install.

 

Un-plug the wire from the sending unit and ground it. Gauge should peg "full" if gauge and wiring are good.

 

the orange one? will try it in the AM

 

I have a problem to ad to this thread.
The pervious owner pulled the tank out of the cab in my 72 f250 before I bought it. The fuel gauge didn't work at all, always on E. So I traced the wires from the aux/main tank switch and noticed that the wiring was just in a jumbled mess. So I found the orange wire coming from the tank under the bed and connected it to the orange wire in the main wiring harness under the dash. Now the gauge reads half a tank when I start the truck but never moves.
Any thoughts, advice?

 

Pull the wire at the bed tank sending unit and ground it...if gauge is good it will peg over to full with that wire grounded. Then pull the sending unit, check float and clean the inside of the unit...the resistance card in there gets grimey, clean it with carb cleaner to get the contacts clean.

 

Sorry to bump an old thread, but bought a 72 F250 today, fuel gauge not working. Googled for a wiring chart and saw this thread. Slapped myself, walked out to the truck and flipped the switch. So thanks OP, 2 years later

 

Always the easiest things that stump us the longest!!

 

To be accurate the one on the floor is a Selector Valve.