So my 1997 ford f150 with the 4.2 has almost 200k on it. My sister was driving it home from work when it died. So I drive over and find that fuse #24 has blown. I replace it and she drives 30 ft down the road and it pops again. So I replace it again and it pops as soon as she goes to crank it. Any one have any ideas as to where I should look next? I don't know much about electrical issues when it comes to vehicles with a brain. I checked spark and fuel. The fuel pump isn't getting power, so I don't know if I can run a new line to the pump or not with it having a brain and all. I'd rather find what's broken and fix it personally, but at this point anything to save my new truck from her bad driving :-)

 

Do NOT run a new wire, that won't fix the problem.

Check for the O2 wires melted onto the exhaust, that's the most common thing, especially if some work was recently done around the engine, exhaust, or transmission.

 

Just checked both O2 sensors and the wires are good.

 

I could be incorrect on this but for your year and V6 motor equipage you have the following circuit.
Follow it closely and use logic or you will have to let someone else trouble shoot your issue.
First, we don't go running wires as a repair unless absolutely proven to be the only repair 'after' proving the fault.
Here is how it goes; As soon as the ignition is turned on it brings up a relay called the PCM POWER RELAY as shown in your manual.
The contacts in this relay close through power from fuse 24 to a second relay called the fuel pump relay.
The harness 'RED' lead between these two points is grounded for some reason.
This is why the fuel pump does not run when this relay cannot operate and pass separate power from it's fuse 19 to the pump circuit.
I have diagnosed it for you, so now it's up to you to continue on and work to find the source of the ground or have some one comfortable with doing so.
Reference Haynes Manuel first, page 12-18 where it shows the PCM power relay and RED lead from it's contact then go to page 12-22 and fuel pump relay A a red color coded lead input.
This line likely has a hard ground that is blowing the fuse 24.
If you keep putting fuse 24 in and blowing it, you likely will burn the PCM relay contacts as well from the high currents due to the short..
Then you end up with two faults.
Re read this and reference the Haynes manual until you understand, or show it to the person who will attempt to find the fault from this information.
Good luck.

 

There are about 15-20 sensors and solenoids that run off that circuit (#361, red wire). You might have a wiring harness chafed and shorting to ground or you might have one of those individual devices that has shorted internally.

Finding it is going to require knowledge and perseverance or luck.

Good luck!