I've reread all of your posts and to me the door switch seems to be working correctly. So forget everything you saw on YouTube, everything, that was for trouble shooting a PRE 1999 controller and motor. You have a 1999 or later controller and motor.
Google, Kwikee Step Manual #888. Download and print out that manual.
Referring to that manual, trouble shoot your steps.
Now do not get concerned about what you may read in the Google search results about there being different manuals for different steps manufactured in different years. Download the #888 manual.
After assuring that your controller ground is good(it is #12 and has green insulation), start the trouble shooting procedures.
Now if you want to know what specific controller you have in order to determine when the Motor and Controller were made, look for the 10 digit number imprinted on the black controller mounted neat the steps. It's not really of any value to know. Manual #888 covers them all. There is a manual that is virtually the same as the #888 that was printed by Lippert who now owns and produces Kwikee steps.
With the information you have given us so far, your controller ground(not the Magnetic switch ground)is bad or either the controller or motor is bad.
Manual #888 has trouble shooting instructions to identify the exact problem.
For a more comprehensive timeline of the electronic controls of the Kwikee Steps, check the archives of this site for one I wrote several years ago, 2011 or there about.
I am not an expert, I just learned all of this from reading posts found on RV.NET and the result of many, many Google searches.
Occasionally Chris Bryant will respond to posts in the Tech Issues section of the Forums. He is an expert and a lot of this info came from him.
I will add a disclaimer to all of this, I am camping in a remote area and do not have access to my home computer and so I am relying on memory for DATES, I don't try to hard to remember them as they just clog up my memory banks.
Good luck and as stated several times #888.