What kind of braking system do you have on the towed? (Many of them eat battery power and many towed's do not have all that much to spare epically if they have a few year on 'em.
There is a system called Towed Charge, it is like the Trick-l-start but for your towed, Charges the towed off the MH battery when driving.
I used the US-Gear Unified Brake Decelerator on my first towed, Came with a system (not towed charge) to charge the towed battery, I modified it for my new towed (Diferenc cables) and it works well, I also added a connector in front of the MH for the towed so I can maintain the towed battery when parked in a campground.
Very happy
System consists of w circuit breakers (one on motor home one on towed) and 10 Ga Wires, running to the grill on the towed (Well in my case under the hood) and to both ends of the motor home,, Anderson Power Poles (30 or 40 amp, bigger than the breakers which are 20s) and the umbicial cord (10Ga "Zip" cord (Actually speaker wire) with anderson power poles on it.
Use of anderson's is optioan.. You can use any good 2 pin heavy duty connector, they are just real nice cause it does not matter which end of the umbical i grab it hooks up both way. Andersons are asexual.
Very happy with the result. OH, do make sure you run a good GROUND lead, I had ground issues on the motor home end o the lighting connector, Fixed those too.