Three o'clock this morning my truck decides it should try to start itself. Starter is cranking away as I run outside in my undies (in the rain). Without the ignition on it, of course, it wouldn't start but not for a lack of effort. Pulled the - battery cable and that ended that. Has rained very hard for a couple of days so moisture was everywhere. Inside the engine compartment also. When I pull what I suspect is a connection wire from the ignition off of the solenoid (passenger side inside fender) the battery can be reconnected. Touch that wire back to the solenoid and she wants to run. Can the solenoid fail in such a manner that power continuously goes thru'? Or is it possible that my ignition switch is staying hot? This was really strange.

 

If it stops cranking when you remove the ignition wire then I doubt its the selonoid. Check to see if water is getting on the inside of the firewall behind the brake pedal area..