You might give this a try and look at the broadcast messages. I have mine in for the same thing, but don't know the outcome yet.

Chris




2005 F-Series Super Duty Factory Trailer Brake Controller Tips: Diagnosis procedures for the Towcommand system is in the workshop manual, section 206-10, Auxiliary Brake System. All voltage tests sould be made with the controller at the maximum gain setting of 10.0. Brake controller output voltage increases with vehicle speed. In park with the controller fully applied manualy, the output voltage on trucks built before 3-23-05 should be greater than 1-3 volts; after 3-23-05 greater than 10-12 volts. Controller output with the brake pedal is the same for either build dates. Full voltage is only available above 15 MPH. The Towcommand system works in both forward and reverse. Broadcast Message 3286, 4312.
When installing an aftermarket controller on trucks equiped with a factory installed controller, the factory one must be left intact and the aftermarket controller installed separately. Broadcast Message 3332, 4080.
The Towcommand system is ment to only work with electric trailer brakes and not surge or electric over hydraulic brake systems. Broadcast Message 3179.