Ford F-250 integrated brake controller issue. Help!

[TAArrowood]

Hey guys I got something going on with my trucks Trailer brake controller. My truck is a 2008 F-250 Lariat. Every time I start it it immediately displays a “trailer brake controller fault”. If I hit the reset button it goes away. The controller seems to be working perfectly normal as far as functional lights, etc. I have put a 7 way plug tester on the trailer plug and all the appropriate lights,( brakes, turn, 12 volt charging, etc are working. If I use the manual controller sliders I get braking power at the plug. Problem is that if I set the gain all the way to 10 and press the brakes no braking signal/power at all. Anyone have any ideas,? Also, on the chance the factory plug had corrosion I replaced it with a new one before the test. I’d appreciate any ideas. Thanks.

 

[TAArrowood]

Ttt

 

[BRTreedogs]

No first hand experience.
But I’ve seen a few videos of ford trucks having a lot of corrosion issues at the plugs.
I think there’s another plug up in the frame a couple feet forward where the wiring splits to go to each tail light etc.

I saw one that was all green in a video a few weeks ago.

 

[Machingeaneer]

If you're getting power at the plug on the bumper when you use the manual slider but not during normal use that sounds like the controller. My understanding is they just pop out of the dash and have a plug that connects to the harness, should be relatively easy to try

 

[TAArrowood]

I got a tester and tried it. When I work the slider I get power at the plug, but when I press the brake pedal no power to the plug. All the other connections get power correctly at the plug. I’ve seen a couple comments saying that the controller may not be getting a signal from the brake master cylinder which tells the controller that the brakes have been engaged. I’ve found a couple used controllers, but I have to buy them before they’ll allow me to plug them in and see if it solves the problem yuk.

 

[Machingeaneer]

I got a tester and tried it. When I work the slider I get power at the plug, but when I press the brake pedal no power to the plug. All the other connections get power correctly at the plug. I’ve seen a couple comments saying that the controller may not be getting a signal from the brake master cylinder which tells the controller that the brakes have been engaged. I’ve found a couple used controllers, but I have to buy them before they’ll allow me to plug them in and see if it solves the problem yuk.

If you find a wiring diagram you can check the incoming signal from the harness when you hit the brake pedal. If you're getting power there it's probably the controller, if not then it's upstream and you need to work your way back to the pedal.