We had 3 hensley brake contollers on 1 trip last year. Some how we got home safe after we stopped and bought and installed a Tekonsha Prodigy P2 Electronic Brake Control. Hensley makes the worse brake contoller i have ever used and only bought it because of the quality of their hitch system. It is very poorly designed, built and functionality.
If it did not have the manual control on it we would have been killed when a semi "T" boned us. All in all when you manually lock up 3 axles you will stop a 34FT AS.
Save your life don't buy this product.