Just to share my story for future searchers since my search was fruitless (other than ABS sensors going bad on Gen 8 F150s).

Work Truck: 2007 XL Reg Cab Short Bed, 4.6L, 3.73 LS 2wd, Hancook Dynapro highway tires

Got into some loose sand on the job site. Rear end sank down, jimmied back & forth, sinking further... long story short, L.S. saved my hiney yet again (it's a daily event).

After getting out, the ABS and brake lights were on. First thing before drive anywhere, I checked the brake fluid and checked for leaks. Everything was fine in the fluid department. Turned off the motor, started it back up, and the lights were still on. Not too surprised. Then, I disconnected the negative battery terminal for 1 hour. Reconnected. Still on.

Next, I hosed out the crappy XL steel wheels (with the nasty mud catching lip that trows the wheels out of balance something fierce...) being sure to get the grit from between the calipers and the wheels, while hosing the calipers thoroughly also.

Fired back up, NO MORE LIGHTS.

The end.