[ricm]

I use the SS-tronix system on all my trailers - the system does have a test feature which turns on all the lights on the trailer, until it receives a command from the I/R LED on the truck. Whilst I haven't tested other scenarios, I imagine its possible that if the trailer lights are turned on and you remove the I/R signal, then the receiver unit in the trailer may hold the most recent command until a new signal is received...ie. lights stay on when the truck is disconnected.

I have added a switch to the support legs so that when the legs are down (ie. trailer disconnected), power to the receiver unit in the trailer is turned off so all the lights go off too. the unit powers up again when the legs are raised, which only happens when there is a valid signal from the truck LED. Added bonus is it saves trailer battery life....