Troubleshooting a Brake Controller that Only Activates with Manual Override Lever  

Working on a 2009 F450 pickup, where we dont seem to be able to get the trailer brakes to activate...when pushing the brake pedal. It will activate the trailer brakes if/when pushing the integrated brake leverfoot to the left, just nothing being noticed when the service brake pedal is pushed...or at least not feeling the trailer holding back. Upon checking the 7 way plug not sure if this would have any bearing on why the brakes are not activating? there is no power at the 12V position of the 7 way plug. I dont have an electrical schematic, so Im unsure of where this particular wire would be connected to the 12V system, or if/where this fuse would be located on this vehicle? Someone mentioned that power isnt sent to the trailer, until the vehicle is in motion 10 mph? thus I dont know if this is his theory, or if its reality, as he says Ford confirmed this to him? If so, should there be power showing up on the blue wire, if the vehicle is stationary? All lights tail lights come on fine on the trailer when plugged in, as well as the signals all work fine just having an issue getting the trailer brakes to come on when the brake pedal is pushed. Is it possible there is sensor or something at the pedal somewhere that might be creating the issue? Sorry for all the questions, but this has been an ongoing issue for a very long time. Thanks in advance!

asked by: Dale W