Mecheng.

Welcome. I hope it provides some help for you in your quest.

Let me add that this... When I finished, my fuel guages do not work either, but then they did not work before I experienced this problem.
Both tank sending units for the fuel quantity were replaced by Ford in 1989 or 90... thereabouts. They worked for a couple of years and then quit. They have never worked since.
I understand that the 1987 F150 has sending units only in the tank, not pumps. There are later models that have both pumps and sending units in the tanks. I dont know what your 85 Model has, but I have heard that if if you have combined sending unit/pump and the your guages wont work, you wont get the pump to work either. The 87 model and later models have a rail pressure pump to get the psi up to the needed level (58 psi -- I think) I have also heard that the toggle (front/rear tank) switch can cause the same symptoms.

Anyway, I dont know if any of this helps you, but I would for sure be checking the wires at the NEG battery terminal. Clearly there are different circuits for starting, and the fuel system..... at least on the 87 Model.

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