Ice Dispenser auger won't stop dumping ice into chute

Question

I have a 9 yr old Kenmore side by side fridge (Model #25355699407). The external ice/water dispenser panel leaked for years, eventually bubbling out the exterior paint, and rusting the door. I removed the ice/water dispenser panel to refinish the door, which involved disconnecting the ribbon cable which connects the Dispenser power board to the Dispenser Control board. Now, when I re-connect those with the ribbon cable and plug in the fridge, the ice dispenser auger immediately starts dumping ice into the external chute and won't stop.

I've tried/tested:

1. Replacing the ribbon cable - same result
2. Testing/replacing the micro-switches - same result

My next steps are to replace the Dispenser Power Board or Dispenser Control Board, but as these two parts run around $150 EACH, I'd like to know if anyone has any advice, specifically regarding:

1. How to figure out which of the two boards may have failed
2. If I start with one board, and choose the wrong one, am I at risk of damaging the other?
3. Is there any other part, inside the ice maker itself, which may have failed? I'm a little unclear about how the dispenser controls "talk" to the auger.

At this point, it is actually just about as expensive to buy a whole new door as to replace both circuit boards, which leaves me pretty frustrated.

Additional curious note:
The last time I put everything back together and connected the ribbon cable, with the refrigerator still unplugged (and had been for at least 15 minutes), I saw a flash behind the Dispenser Power Board.

Answer 1

Short Answer: Replaced both boards, and this fixed it.

Despite lots of excellent help from others on this forum, concluded that I couldn't adequately test the boards without risking damage to a new board by connecting it to one of my current (status unknown) boards. Very appreciative of the caution regarding these parts' sensitivity to static discharge, as even the chat help person from the parts website didn't know about this (but the parts packaging confirmed that you need to wear a wrist strap grounding device and handle carefully to avoid damaging the new parts).