i made these to control my traxxas erevo lights wtih arduino. i put Neopixel lights back of my car, F1 style and power leds stays on front.

5v relay -> D4 ( Red=D4 / Gnd=Gnd)

Neopixel -> D6 (!! Gnd =Gnd / Vcc =3.3v)

Rc receiver Ch3 -> D7

Rc receiver Ch4 -> D8


You should connect your arduino and rc receiver to computer to analysis your receiver signal changes. Then fallow your signal changes from serial monitor while you moving your ch3 and ch4 switch. You will probably have to change signal values from code.