PotteryEnabler

Fired up great and in record time to hit cone 6. 
Yes, clearly I flushed out the electronics gremlins and Heisenbugs. I'm going to say it was the switch, since that was my most clever, daring, and skilled work. That or my wife was correct and I just managed to "turn it off and on again" enough times. 
 
 

Well, I put it all back together carefully this afternoon. After attempting some of PeterH's solid multimeter testing advice but becoming more confused the more things beeped at me, I gave up and just fired it up.
It VERKS! It fired up and the correct elements turned on and got orange.  I actually have no idea what the magic sauce was in rewiring or grinding down that switch hub. We'll see if it lasts through a glaze firing tomorrow. I will admit the brand new element gets a little hotter faster, but they all got there. Resistance is close to the same on all of them, so I don't think I'll replace them all. 
Thank you all for your help and I'll wager that this is not my last time with a pottery related problem. My wife and son have taken up pottery as a hobby, and I have apparently taken up electrical engineering, induction motor repair, refractory masonry and material science along with various other brain growth activities to keep them at it.
As payment for your assistance, I colorized the wiring diagram for us all. 

It looks to me like the top element (in the diagram, not necessarily in the kiln) is only fed by one of the 120v lines (the upper one in the stylised plug/socket). Although you say that both 120v lines are getting to the controller, is the upper one also getting to the switches and/or elements?
PS
>I have peered closely at that wiring diagram and wished for higher resolution a lot the past few days
For a different kiln, but probably/possibly the same circuit
https://content.invisioncic.com/r278179/monthly_2021_11/AFFD763E-B04E-4A36-A21B-049717307DB1.jpeg.d8d19f63656d62487cfde60f695535d2.jpeg

... asking for coloured felt-tips on the different styles of dashed lines

Well, I put it all back together carefully this afternoon. After attempting some of PeterH's solid multimeter testing advice but becoming more confused the more things beeped at me, I gave up and just fired it up.
It VERKS! It fired up and the correct elements turned on and got orange.  I actually have no idea what the magic sauce was in rewiring or grinding down that switch hub. We'll see if it lasts through a glaze firing tomorrow. I will admit the brand new element gets a little hotter faster, but they all got there. Resistance is close to the same on all of them, so I don't think I'll replace them all. 
Thank you all for your help and I'll wager that this is not my last time with a pottery related problem. My wife and son have taken up pottery as a hobby, and I have apparently taken up electrical engineering, induction motor repair, refractory masonry and material science along with various other brain growth activities to keep them at it.
As payment for your assistance, I colorized the wiring diagram for us all.