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Discussion Starter #1
Ok. So I just got a 96 Bronco with a bad fuel pump. I dropped the tank, pulled the pump, confirmed it was bad. It sucked up a deteriorated sock and burned the pump up.
I replaced the fuel filter. Added gas. When I turned the key the pump doesn’t do it’s 2 second prime. I checked all the fuses and tested the relays for the PCM and fuel pump. All good. I jumped the fuel relay and the pump runs. So everything from the relay back is good. With the key on I have power to the light blue/orange, red, and yellow wires but not the dark green/yellow wire. So at this point I suspect it’s the computer. I pulled it out and found a good amount of Rust on the case. The wiring connection is good and clean. I replaced the PCM. And still not getting power to the pump. What am I missing? I’ve checked every ground I can find visually and with a power probe and ohm meter. Any help is appreciated!
 

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No Power to connection with key on. Checked the inertia switch and it’s good. Relays are good. Pump runs when I jumped the fuel pump relay. But the truck will not run that way.
 

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Is there power (on and off) to the relay with the key switched on and off?

Is there power to the inertia switch going in and out?

>>>>>>>>>>>>Action
 

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With the key on and in park there is no voltage to the green/yellow wire that runs to the inertia switch. When I apply a jumper to the circuit, the pump runs. Everything from the relay to the pump is good.
New update....
I put the truck in neutral and turn the key and the pump kicks on. Still will not start.
 

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With the key on and in park there is no voltage to the green/yellow wire that runs to the inertia switch. When I apply a jumper to the circuit, the pump runs. Everything from the relay to the pump is good.
New update....
I put the truck in neutral and turn the key and the pump kicks on. Still will not start.
The actual "ignition switch" is really many switches working in parallel. It is possible for one switch to fail, so even though the engine is turning over, that is NO Guarantee that all other circuits are getting power. Verify power to necessary circuits. I installed a new wiper motor once, it turns out the old wiper motor was fine, the problem was faulty ignition switch.
 
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