ok, i put a new sensor in my diff. and now it doenst work. i disconnected the neg battery cable and installed it, went for a ride and the speedo is dead and i still have the lights on.

 

Check the wires and the plug to the sensor. And what brand sensor are buying ?

 

ok. and im buying the napa brand sensor. i dont know what brand that is

 

dude I totally had this happen and I thought I was toast. I am telling u to check your wiring connections unDer your steering wheel. also check your transmission output speed sensor. that is another solution to this problem. part for that is only 13 dollars at autozone

 

He says he replaced that one already. Maybe that one is a defect and or the wires/plug to that are bad. Thing is, if the ABS and brake light's are on, the sensor on the tranny should not give a code for ABS/Brake lights. It is quite possible there are two different problems. Or there is simply a wire/plug problem.