09 Ford F-250 6.4 Never Had Any Issues Today I Plugged In A Brand New Trailer And Distinctly Remember Turning The Reverse Sensors Off, Later In The Day I Need To Use 4x4 only to discover it's not working now either, then i try tow haul mode same result, everything else is fine, i plugged trailer back in and all lights on it function as they should. Checked fuses and they are good anyone have any idea on where to go next?

 

Probably to the dealer to check the computer and possibly do a re-flash.