First let me say that wiring explanations from one website do not always match with another website. For example the oil pressure sensor is listed as 2 wires on one site and 3 wires on another site. My truck is 2 wires. So wiring info is confusing.

On my truck the wires going into and out of the ignition switch are 2-3 times thicker than the wires going into and out of the neutral safety switch. This makes no sense since it’s my understanding that the wire coming out of the ignition switch goes directly to the neutral safety switch. Some websites speak of a neutral safety switch “relay”. But don’t tell you where it is, if there is one. But that would make sense of the 2 different thickness wires.

So this is what I have done so far:

I manually jumped my starter off from the “S” terminal on the solenoid, and everything works. So the solenoid and starter are good.

Then I pulled the ignition switch off the steering column and manually activated it with my screwdriver instead of the key. And I pulled the wires off the neutral safety switch and jumped them out(Bypassed them). In the crank position 12V shows up at the neutral safety switch. That makes the ignition switch good. And with the neutral safety switch jumper out 12V should be going to the starter. But the solenoid makes no clicking noise and the starter doesn’t turn. And we know that’s good. Could there really be a relay or fuse for the neutral safety switch?

 

Did you check the crank fuse at the fuse box. I think its a 5 amp fuse and its usually at the bottom right corner of the box. Put the key on run position and check for power at the fuse. If no power, check the fuse to see if its ok. You may also want to remove the fuse and check for 12v at one leg of the fuse to make sure there is power coming in. If you supplied power to the S terminal of the starter and it worked, than it sounds to me that you have a break in that wire that comes from the switch to the starter. Its possible the neutral switch has a problem. Turn the switch to crank position and when you do that, try shifting gears from park to drive and see if it tries to start. Of course make sure you have your foot on the brake and even the emergency brake on. This are just suggestions. You really need to get a service manual for your particular truck to do some troubleshooting. Another thing you can do is to run a wire direct from that 5 amp fuse to the S terminal on the starter. If you decide to do this, put a fuse link in that wire to protect the circuit.

 

If your truck cranks when you jump the solenoid then it needs replaced because when you jump the S terminal you bypass the solenoid entirely.