BMW Repair: about the abs on bmw 1987 325e, reset tool, abs light

Question
hi i have a problem with my abs system first i check the 4 sensors on each wheel the rear sensors it works perfect because i check with a multimeter i put in ohms and sensor they reads ok then when i check the front sensor they dont work with the same method i find in a junk yard another ones i check in a junk yard with my multimeter and works perfect and then i change the front sensors and i see the light doesn't go off some friend tellme you need a diagnosis in a bmw garage or buy reset tool similar like service reset tool another people tellme when you change the sensors the abs computer feels or reads the new sensor i changed the lights go off and i dont now what you recommend in this case to do it if you can helpme ill be appreciated to much thanks

Answer
although you have check the sensors and they seem to work  the wiring itself could be at fault.The ABS light will go off if the problem is repaired.You have to go a little deeper and check the wiring to the computer,The wires have a tendency to corrode inside the casing so look for wires that are bubbley or green.