I found an old thread from 2017 in regards to this.
If I get handed a car by a teammate within RFactor, I cannot get FANALEDS to output anything at all.
Even if I wait until I've been handed the car and then launch the program.
It seems from the other thread that a fix was attempted...is it in the latest release version, or beta version? As it doesn't seem to work...
Can help with any debugging / info you may need.