Goddamnit originated from spain where it ment something like, "horsecock" or "damned be thy son". Noone knows how, or why, it has been common in the English language.
From it's originated state, it has become somewhat false in the English language, where many still belive it's just "God Damn It!" without spaces. God himself knows this is wrong.
Today it means something (1.) important, and/or (2.) something worth making a statement over. It can also mean that you are (3.) embarrased over something.
1. We need this in today goddamnit!
2. This will be something that peoplewill talk about, goddamnit!
3. Goddamnit..
(Noun) The part of your automobile that is broken and needs to be repaired. Regardless of the part that is broken, it is always referred to as the goddamnit.
I have to go wrench on my truck. The goddamnit is broken again!
A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"