4KSQ - Won't start, not starter

[Tim & Holly Pellowski]

 Q-listers,

Help!

 My '85 4KSQ has been down for 4 weeks now.  When you turn the key, there's 
nothing at all, no solenoid click at all.  I pulled the starter replaced 
the ground strap from the armature to the solenoid.  Tested starter, worked 
fine, pulled about 105 amps (as opposed to a new one at 90amps).  My 
battery is good, has a 12.3v charge.  Terminal 50 wire has the insulation 
failing off but I don't understand where it goes to.  Is it possible for 
the ignition switch to have gone bad that quickly?  How do I test the 
ignition switch?

 Anyone have any ideas for me?  I'd really like to get it running again. 
 By the way, this happened all of the sudden.  The 4KSQ worked fine one 
night and the next morning nothing.

 TIA,

Tim Pellowski