Wow,,
I just bought a tail unit making the same assumption, that it would work like Lados, now after reading your post I see there is no signal wire.
My bad for not doing my homework,,

I was thinking maybe a type of mechanical current reversing controller might work, but I just tested it, it holds a about 1.6 amp load when it reaches the end of the cycle,, it doesn't power down. Looks like the Robart controller is needed