I had the same issue. I first noticed something wasn't right when I was driving to work and the ABS light came on while I was stopping. I thought it was because one of my brake calipers is seized (I know I plan on fixing it ASAP), but the light went off about a minute later. ABS light came on again just before I got to work and then went off before I got to the parking lot.
When I left in the afternoon I noticed the shifter wouldn't come out of park, but I let go, pressed the brake again and it shifted into Drive. Later that night, my wife got in it and couldn't get it out of Park. After trying for a few minutes she got it into Drive and claimed it was because she turned the steering wheel to the left before trying to shift. I have no idea why she thought that did it.
The next day I couldn't get it in Drive and got my son to look at the brake lights while I pressed the brake. No lights on. So between that and this thread I figured it had to be the brake switch.
I found a much easier way to do it than what is described in the PDFs above. Follow the instructions in this video:
https://www.youtube.com/watch?v=3Sja-CXlfBo&list=WL&index=12&t=0s
The switch is behind the brake pedal and slightly above it. It's easy to see without removing any panels or the brake pedal. It has a blue connector, remove that, twist the brake switch counterclockwise (like you would when replacing a headlight) and it should come right out.
Put the new one in, but make sure you push it all the way in before twisting clockwise to lock it. If you don't push it in far enough your brake lights will be on with the brake released and turn off when the brake pedal is pressed. Reconnect the blue connector and you're good to go.
This may or may not have also set off my VSC Trac lights. I just finished some repairs that spanned a couple months and I thought the VSC lights meant I needed to do a Zero Point Calibration. I did that anyway after replacing the switch and now my VSC lights are off.
Hope this helps someone else.