Switch is momentary, tested with a multimeter. Voltage on the output wire is 5v when it's not pressed, 0v and grounded when pressed, back to 5v when released. Results are repeating. Assuming the 5v is for the button lighting as the led inside turns off when it's pressed. I'll be returning ground to the output wire from Arduino on a single click action to retain it's original function and on a hold action use another wire and relay for the additional lights.
Working on getting a wiring schematic, vehicle is a 2018 and a brand new model so free schematics aren't available yet but I've reached out to some dealer techs to see if they can snag the wiring for the switch and front lighting.
Essentially need to know what type of relay can I use that can be triggered via an Arduino output and on it's output end can handle automotive load or trigger a standard automotive relay.