I spoke with my buddy in the Tech Services Department at Tekonsha, who tells me that he suspects that when the controller was installed, it was connected to the wrong brake stoplamp switch. It's possible that the wire it's hooked up to allowed the controller to work properly over the last six months, if you haven't used the manual brake switch before. The red wire of the brake controller should be tapped into the green/white striped wire that exits the brake stoplamp switch.
When the manual... view full answer...