you could try holding the key in the start position and move the shifter through the gears to see if somewhere you have contact with the starter. HOLD THE BRAKE PEDAL DOWN BECAUSE IF THE ENGINE STARTS WHILE YOUR ACTUALLY IN GEAR THE TRUCK WILL TAKE OFF!
Even if the neutral safety switch is not adjusted correctly it shouldn't make it so the engine won't run once you got it to crank over. Is your security
light on or flashing?