Tekonsha ~ NO or NC contacts?

[Aznomad450]

Model #2010
I have continuity through switch
The breakaway has a broken pin tip and I assume the tip is inside unit
Inserting the remaining piece of pin in unit does not change continuity

I was under the impression that the switch inside the unit is a normally closed and inserting the pin opens the contacts, when pin is pulled the contacts close. Right or wrong?

Here' where it gets strange. I bought this trailer 2 years ago and have used it on many trips. Never thought to pull the pin to check the brakes and due to other circumstances never thought much about not feeling the brakes engage when I tap the brakes. I just kept adding gain and going my way. I decided to fix the brakes once and for all and pulled each wheel, cleaned, reassembled, and adjusted. Plugged the 7 pin trailer connector into the truck and blew a fuse. I suspected the breakaway thinking it was shorted. Well, if it is a normally open contact, and the switch was closed, then I had voltage applied to my brakes forever and have burned out the magnets. In fact, I think this might have occured with the previous owner because I am not sure I ever did..... I can assure you that I am not an incompetent but all I know is I ordered a new switch from Amazon and should have it in 2 days. Thanks for the feedback and allowing me to bend your ears.....