Also, if (like me) you accidentally leave the black sensor above or to the right of the channel plate it won't align properly to install into the detent arm.
Don't remove the channel plate to correct this. Instead move the stepped detent plate way around to the right so the internal switch is no longer surrounding the left edge of the stepped plate. Then the left edge of the plastic internal switch piece can be coaxed over the edge of the channel plate. After which you can turn the stepped plate back inside of the internal mode sensor.
HTH, I almost unbolted my channel plate to position this and thought I'd share my time saver.
