my abs and brake light has been on since i bought the truck and after doing some reading i figured that it might be the rear sensor, so when I was at autozone ( or the twilight zone depends on who's working) I picked up a rear speed sensor. Then, i heard if the speedo is working (mine was), probably not the rear so i didn't install it figuring maybe i'll stop by my friend shop and use the snapon scanner that can read abs codes when I get a chance. Today I put the back axle up on some stands and pointed it away from the house and ran it in 6th gear, because i'am trying to isolate a 60-70mph heavy vibration and guest what no speedo. So, with the truck already in the air and the sensor on the front seat I gave it a shot. No light! Back to diagnosing the vibration.