i think it's doable, but make sure your phone and steering wheel controls are compatible with the 4-pin setup. you might need something to interpret the button presses for the TRRS jack. wiring mic/gnd through the button in/out with the right resistors should work for the phone controls. your paint explanation looks solid, good luck!
i think it's doable, but make sure your phone and steering wheel controls are compatible with the 4-pin setup. you might need something to interpret the button presses for the TRRS jack. wiring mic/gnd through the button in/out with the right resistors should work for the phone controls. your paint explanation looks solid, good luck!