We have that model on a Chev Avalanche. It usually works well but sometimes does not seem to work. It relies on "radio" transmissions. I sometimes do not get signal that brakes are working. Could be brakes are working but signal is not received in RV. We have 40' RV so maybe too far for some signals and more prone to radio interference. When wife is following me after disconnecting tow, she says brakes work very well. (The RV will turn on tow's brakes even when tow is disconnected.) (Of course the brake system can be turned off when disconnected, but sometimes forget). I have been told that my Pressure Pro tire monitoring system can interfere with SMI's radio transmissions. A couple of times when not getting good signals I turned off the Pressure Pro but it made no difference.
John Abbott, 40' Winnebago Journey 2004
Chev Avalanche 2004 Tow