Classic/Antique Car Repair: selenoid, solenoid, 12 volts

Question
I disconnected the ignition switch wires from my selenoid , so I could replace the starter and now I don't remember where the purple and the black&red stripped wire go. I have a 1965 Impala. I traced both wires and they both go to the ignition switch.  On one side of the selenoid is an s terminal and the other side is an i . Any help is appreciated. Steve

Answer
The one that goes to the "S" terminal on the solenoid goes to the "S" terminal on the ignition switch.  The "S" terminal is the one that gets 12 volts ONLY when the key is twisted to the Start position.  

The other one goes to the "I" terminal on the switch.  That terminal gets 12 volts when the key is on AND when it is in the Start position, both.  If you connected these two wires backwards, the starter would try to keep cranking after the engine was running, even if you let off on the key - you'd have to turn the engine off to stop this from happening.

Dick