bad ignition switch?? im stumped

[c20pickup]

could somebody help me a l;little bit here.. have a weird problem
im running a painless wiring harness, my old ignition switch (has been sitting around for about 3 years due to the restoration process) and when i turn the key to the on position the engine stays cranking, it also remains cranking when in the accessory position and also in the start position. thinking it may be the painless ignition plug, i pulled it off and checked the wires and they all matched to the correct positions on the back of the ignition switch (accessory went to accessory, solenoid went to solenoid, etc) so that ruled out any crossed wires in the plug itself. so my next step was to check under the hood, with the starter solenoid wire off the starter i turned the key to the on position and proceeded to check all the engine connections for power (distributor, electric choke, etc) i even checked some under dash connections and they all had power just like they should in the on position, the trouble is, even in the on position my starter solenoid wire remains on. my next step was to take the plug back off the ignition and run a jumper wire from the battery wire on the ignition plug to the battery terminal on the ignition switch, and in the off position i tested all the terminals, and just like they should they were all off, so i turned the key to the on position and all the terminals turned on (accessory, ignition) but the starter solenoid terminal still remained on/hot. im not the best with wiring but i tried troubleshooting everything to the best of my knowledge, and everything leads me back to a bad ignition switch, what do you guys think?

p.s. this is a brand new harness, and the ignition switch worked flawlessly when the truck was still together, i dont know if something got corroded up or sticky on the inside from sitting?