Samsung Microwave ME21R7051SS Faulty "door" Indicator Riddle

[dchase57]

First, I'm the new guy here. Retired aircraft mechanic (USAF and civilian) and as a side hobby, I do small engine repairs on lawn equipment and small appliances. A few weeks ago while wandering the aisles of Lowes, I stumbled across some scratch and dent under the shelf microwaves and for $99. As mine came with the house 23 years ago and was already having issues, picked up this model. It was still in the open box and with all the protective wrap attached. One of the techs and I pulled it out, looked it over noting a small dent on the side that would be hidden once installed.  Fast forward to two weeks later when my son stopped by to help me swap out my old, dated GE model. Once plugged in, I pressed the "start" and got a "door" message. Upon opening the door, it was obvious the top latch of the door key had broken off.  Replaced the door key (via Amazon at $9) I  still got the "door" message. Opening up the control panel, I pulled the micro switches, (2 open, 1 closed) did a successful continuity check and reinstalled. Another issue was when the door is closed there was a humming noise. That turned out to be the fan, behind the control panel was caught against the frame. I bent the motor bracket back in place.  Now when I open the door, the light comes on as does the fan. This is odd as a broken latch and bent fan bracket leads me to believe this unit may have been dropped at some point. Now I'm at a loss and before I take it down, and donate to ReStore, I suspect something or someone was here before and maybe the wiring is incorrect, or the control board needs replacing.  Open to any suggestions.  Thank You