We have an 05 Monaco Knight and added a brake controller for a trip earlier this year. I contacted Monaco Tech Support and they told me how to find the Brake Controller 'plug' under the dash. After locating that I installed the controller per the instructions and tested the trailer brakes. To my surprise we determined that the trailer brakes were 'engaged' with my foot off the brake, and 'off' when I stepped on the brake. Further investigation determined that my unit was wired with a 'negative' brake switch; in other words the lead from the brake switch was energized when the brake pedal was not engaged; and dead when you stepped on the brake.
After additional research we located a wiring harness in the drivers side front electrical bay that included a wire that was idle until the brake pedal was depressed at which time it became energized. We ran a wire from the brake controller to this bay and connected to this wire. The trailer brakes worked flawlessly after that.
You may want to contact Monaco (check their website under support) and ask about the brake controller harness. They've helped me on several similar queries.
Joan & Steve www.fosj-steve.blogspot.com
'05 Monaco Knight 40PLQ, '05 HD Deluxe, '08 HD StreetGlide & 2014 Jeep Rubicon Unlimited 4x4