Lesli790

I have a ford f150 with dual tanks electricity from the battery is not getting to the fuel pumps. Replaced fuel pump relay and inertia switch is working. What should I check next.

Steve83

This thread:
https://www.f150forum.com/f93/fuel-pump-404498/

JerseyGray

Check the wires for breaks

Jesse Espinosa

I had the same problem. The front pump worked but no power was getting to the rear. Check the fuel pump for resistance with a multimeter. Mine had too much resistance. I replaced the pump and started right up.

txsoutherndraw

I have a 91 F150. Switch for changing tanks went bad. My rear tank is corroded anyways (Since it always had gas being sent from the front which caused gas to come out of the back tank and leak down on the body, that ford thing they had) so I just kept the front tank full. This April of 2021, I drove 50 miles to my Easter outlet. I got there, then when ready to leave, damn thing wouldn't start. changed fuel pump on front (had to use a rear pump because it was Sunday and O'Reilly was the only choice and only choice they had) inverted and made other modifications. Still wouldn't start. So Towed it home for $200. The best mechanic in my world lives in Houston. Anyways, He test electrical and it came down to the fuel tank selector switch that was the beast. Couldn't a switch immediately, among the test the switch test light lit up on the red and red/line wires so I cut them from the switch and directly tied them together. This worked great until October 2021. The wires started staying hot and run the battery down. I believe that good OLD plastic in the boxes made those wires loose. which caused my issue now.. Just so many times can you keep plugging in and out due that OLD plastic. I saudered the loose wires but know it wont plug in to its box. That box is probably bad as well plastic wise. Now, I want to straight wire that PITA directly from that point (where is that)? Meaning do away with the accessory of switch tanking. Direct wire from where to where is my question. No need to mention that my fuse box in the cab needs redoing, I just need some crayon pictures that is simple to allocate what they mean. I know the firewall will be included and that is no problem. I just want a real answer to bypassing this crap that is broke. If anyone wants to be a HERO today, I will cry with joy and happiness.


The black/white, 2 yellows, black, red, red/ orange. The front box is what is behind the tank switch face plate.

I cut the red, red/orange from the switch plate and twisted them together. This worked for awhile. I believe they worked loose and stayed hot even when truck was off.

This box I am holding is where the wire harness hooks too from the selector switch. I stuck my arm up in the dash but could not follow the end. I have had the dash out before looking for that PITA Inertia switch. It will come out easily now.....

txsoutherndraw

By the way, after I put the red and red orange together, the rear fuel pump did work. I changed it back because I didn't know if I would know how much gas was really in the tank.
Boy o Boy O boy.................