Hey guys. PO removed the fuel tank selector valve and was just running off the forward tank. I've replaced both tanks and would now like to re-plump fuel lines and install a valve. I've got everything, but I'm not sure about the wiring. FSM isn't clear on this. I sure hope the wires are still under there. Can someone tell me how this is wired? Pics would be awesome.


Thank you

 

Nobody knows? Any help?

 

Pluming help....

Fuel selector in the environmental panel still there?

78/79 duel fuel tanks frame switch-Duralast/Universal 3 port fuel selector valve used with SW48 toggle switch Part Number: FSV4

Disconnect the wire that goes to the fuel sending unit at the tank. Ground that wire to the frame, making sure the frame is clean. Turn the ignition to the "run" position and watch the fuel gauge. If the gauge swings all the way to full, either the sending unit itself is bad or it has a bad ground. If the gauge stays on empty then either the gauge is bad or there is a wiring problem.

Last schematic page 1/2 way down, r/h side has tank wiring.

 

Thanks 77&79. Yes, the switch is still there and functions. I found the hot wire with a tester and using iPhone video since I was alone. I've tested both sending units and they're good. My valve will be here today, so I haven't actually seen the connections yet. I'm assuming the ground wire is already attached to the unit, and I'm to ground to the frame using one of the valve mounting bolts?


Thanks for the plumbing pic! I wasn't sure which port went to which tank. One of my new senders was bad. I ordered a Spectra unit and it appears to be higher quality.

 

Valve isn't serviceable. Mine has the same issue. Found out after I got it back on the road it was drawing from both tanks. I don't have vents or evap lines so it's the only answer that the valve had deteriorated inside as it did electrically and mechanically make noise, I never check the ports for blow through as my crank subsequently left the conversation and it's been off the road since.

 

D5TZ-9A050-A .. Fuel Tank Selector Valve / Marked: D5TB-9A050-AA .. 5 ports .. Use with dual fuel tanks / Obsolete

1973/79 F100/350 // 1980/83 F100 // 1980/86 F150/350 all with single fuel system

RPN PARTS in Erie PA has 9 = 888-864-9305