Found This. Not sure if it's the same or similar procedure for 2015:
"You can download/print the 2011 F-250 Owner’s Guide found in the Glovebox section of Official Ford, Lincoln & Mercury Owner Site | Personalized Owner Information | FLMowner.com where this information can be found in the 3rd printing:
To permanently turn off the Rear Sensing System (RSS), first look to the “System check and vehicle feature customization” section starting on page 25:
Press the SETUP button repeatedly to cycle the message center through the following features:
Cycle through until you get to this option (found on page 28):
REAR PARK AID (if equipped)
-This feature sounds a warning tone to warn the driver of obstacles near the rear bumper, and functions only when R (Reverse) gear is selected.
-Press RESET to turn this feature on or off. You can also choose to turn this feature on/off when the vehicle is placed in reverse.
This will make it so you don’t have to keep turning the RSS off each time you go into reverse on your 2011 F-250.
One additional thing I found out is that you need to make sure you are using the admin key (MyKey) when you follow the procedure to keep it turned off."
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2005 Ford F350 SRW SuperCab/LongBed 6.0 Powerstroke
QuickTrick's Towing Tune
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