All of the devices are now shipped with a remote indicator and wiring harness. I firmly believe that this should be installed so you will know when it is working. The supplied harness requires that you add yet another cable and 2 pin connector to the interface between your motorhome and towed vehicle. I used a 6 wire interface on my system and incorporated the indicator in it (See my Brake Buddy Wiring page and 6 Wire Connector Page).
My Saturn has the manufacturer supplied car mats which seem to constantly creep towards the front of the car on driver's side. That leaves the back edge of the carpet about halfway between the seat and the brake pedal and my Brake Buddy was setting "centered" on this edge. Every time it would activate, it would rock to the back, deactivate, rock forward, reactivate..you get the picture? The activation device is a metal rod suspended from the top that swings forward to close a micro switch. If the unit is not fairly level and set on a stable base, it will not work correctly.
There is a extension on the back side of the Brake Buddy that is intended to push against the front edge of the drivers seat. Due to the large variety of seats, you may have to become a little creative in order to provide a good surface for this to rest against. The firmer it is, the more effective the device will be. In my case, the Saturn has a foam rubber overhang that the Brake Buddy was resting against and It was pushing itself backwards every time it activated. I finally had to place a small pre-cut block at the bottom between it and an indentation in the floorboard.
NOTE: You can also control the angle that the Brake Buddy cylinder interfaces with your brake pedal by moving the pin up and down in the clevis that goes on your pedal( see image below). This will sometimes help when it looks like it is trying to push itself up out of the floorboard.
The 12 VDC air compressor in the Brake Buddy requires a pretty healthy current from you battery and how often or how much it runs will be determined by how much you use your brakes. The first car I had mine on had a battery that was near end of life but still capable of cranking the little 4 cylinder engine. I bought my Brake Buddy in Columbus at the FMCA rally and killed said battery coming back home to Virginia. Here again, I have added a charge line between my motorhome and towed vehicle(See my 6 Wire Connector page).