Wireless trailer functions are controlled by Infrared.
You can buy the transmitters and receivers from Servonaut, Pistenking etc. (sure there are more brands available)
https://www.pistenking.com/shop/?lan...tml&cPath=5_18
https://www.servonaut.de/shop/en/?ca...ight-Sets.html
Personally, I have no experience with these, so can't help you further.