Car door trigger activated Neopixels/Leds

Alright guys, I will start by saying this is my first post, so I apologize if I did something wrong.

I am very new to Arduino and programming in general, but for the most part I was able to get the pattern for my neopixels completed. However, I want them to come on when I open my doors to my car. My car has negative (-) polarity door trigger wires and I am more then comfortable with wiring my vehicle. I work at a car audio shop so I have access to databases and diagrams and tons of experience in that regard. (if I can assist anyone with wire colors I will do my best!)

So, my question is, how would I make my door trigger act as a switch or button to tell my arduino to activate the Neopixels in the pattern that I chose. In my world I would just hook the door trigger wire to pin 86 on a 12 volt relay.

To help make things more clear, I plan to put a 24 count Neopixel Ring in each of my cup holders. I already have them and they fit great. I also had a pack of 100 cheapo WS2812B individual LEDs that I plan to add behind my A.C. vents. I soldered 2 separate rows of 9 together and hope I can run them on the same Arduino Nano as the rings. I am doing a slowish chasing pattern of blue and white for all. I have that done other then deciding exactly on their speed.
I have already fabricated what I need and I added some water resistant surround to the pixels just in case of condensation.

The only thing that I THINK I need now is way to trigger them, and advise on using the same Arduino. I also would like to know, if possible, how to make them stay steady on after they do their initial “chasing” program.

Once again, I am brand new to this, and apologize if I typed too much, or didn’t provide enough detail, or am asking for too much.

ANY help is defiantly more then welcome. And like I said, if I can assist anyone with similar vehicle projects, I do have access to very reliable vehicle wiring diagrams.

Thanks guys!!

so I apologize if I did something wrong.

Apology accepted.

Haha, well good.
What did I do though? lol.

Hopefully, you have some advise on what I did wrong, or better yet you have a simple solution to use my door trigger as a switch.