Now i am startin to lose it..

I replaced the starter solenoid (the one under the hood) and i put in a new ignition switch.

The thing still cranks over and keeps cranking even when i back off the key. This is nuts...

I am hearing about another solenoid on the starter itself ? Whats that all about?

Someone please help, i am going crazy !! Plus the snow is coming and its my plow truck.