Ok this truck hasn't run since last year because of this and we need it running.
There's a plug with 2 wires, both go to the inertia switch, 1 has 10v or so power, the other goes to the fuel pump. if I apply direct from the battery + it kicks the fuel pump on. If I unplug this and test these two wires, the one has the exact same power as the battery, and the other goes to the fp.
Now if I jumper the first wire to the fp wire suddenly there is no power. The 10v disappears.
Why does the power disappear?
I've tried with 3 separate relays, it's not a relay problem. However there is a wire to the batt ground that when grounded the fuel pump relay clicks, and the 10v at the plug becomes 1v.
This is such a confusing mess what is wrong?