Lights/ wiper electrical situation(problem)

[67sss]

So here's the scoop. The parking lights and tail lights come on when I turn the ign. to the on position, not cranking the engine.
I've tried replacing the light switch, didn't help. Below I have 2 pics, 1 of the plug and 1 diagram. Can someone tell me which plugs on a light switch on a 68 GMC should be hot? The tail/parking lights will go off if I unplug the light switch, which is obvious, but in electrical eleminate all the easy things first.

Wipers. Whats the top prong on the inside for? got blue/yellow wires for the 2 main plug ins but nothing for the one that is by itself?

Thanks in advance for the help.