Do you tow anything else with your motorhome? If not, you can do what I did. I wired the sense cable from the invisibrake into my 7 pin connector. The toad doesn’t use a brake controller wire to activate the invisibrake, so I wired the sense cable to the brake controller pin in the 7 pin connector. I then bought a 7 pin to 6 pin umbilical and installed a 6 pin plug on the front of my towed. The four standard wires (left turn, right turn, brake, ground) take up 4 pins in the 6 pin. 12 volt positive and invisibrake sense wire take up the other 2 pins. 12 volt positive goes to the toad battery with an in line fuse to help keep the toad battery charged up while towing.
If you do tow other things with your motorhome and need the 7 pin plug wired standard for other things, you could wire a second 7 pin at the rear of the motorhome. Jump the 5 standard connections from the existing 7 pin (left turn, right turn, brake, ground, and 12 volt positive) then add the invisibrake sense wire in as number 6 (leaving the 7th pin unused). Make sure you label which 7 pin connector is for what so you or someone else doesn’t mix them up.
This way the only electrical connection between the motorhome and toad is a single umbilical (7 pin on the motorhome side and 6 pin on the toad side). The only drawback to this method is the toad can’t be towed by anyone else without a little rewiring (or ingenuity). I did put a simple on/off switch in line in my invisibrake sense cable in the passenger compartment of my toad. This way, I can turn the sense cable off for emergencies when my toad might have to be towed by someone else’s rig. Everything else will work, I just won’t know for sure the invisibrake is activating or not because the sense cable is taken out of the equation. For emergencies, I can live with this.
Hopefully this all makes sense. If you need any more information let me know.