ABS Light and Parking brake light on

my ABS Light and parking brake lights are on. They still work and I think its the sensor that is broken. Where is that Sensor located in a 2000 chevy S-10 2.2 L LS I have the same exact problem. Find a solution yet? Seemingly at random my ABS and PB lights will come on, with that the speedo stops working and I have severe shifting problems. Either very late shifts or no shifts at all. Sometimes it will shift into second and like magic all the problems go away, Sometimes, itll finally shift after running at redline and all the warning lights go out but it still doesnt want to shift. The symptoms are always the same but in random order, and come and go very randomly