Controllers normally manage volts and amps comes along via Ohms law...there are
some current controllers, but they are more expensive (both parts and design)
As for using the TV's ABS to ABS the trailer brakes...as long as there is inertia
on the trailer braking system...they CAN NOT be ABS'd well...
Modulation of the friction on cast iron needs to be crisp (fast and short times
between voltage spike). DrumShoe setups CAN NOT be modulated fast enough for any
kind of effective ABS. Trailers with disc setups has the inertia of the on-board
trailer controller between the feed from the TV and the trailer disc brakes