Parking break sensor is above the parking brake, just follow the break pedal up into the Dash, There should be a sensor there like what is on the brake pedal.
Speed Sensor Input (Explorer Gray/Black at console)-
2003-back Ranger: Gray/Black at GEM
2004-on Ranger: Gray/Black at Smart Junction Box (brown connector) Passenger Kick panel I beleive
Here is the link to John's OHC wiring How-to
Reverse Signal I am assuming it is talking about the reverse light wire. I am unsure of this wire color but I would pop your tail light off and see what color it is. Then get under the dash and find that wire. but I am sure someone with a little more knowledge will chime in.