ABS lights go's on and off

it could be a bad ABS sensor.. or loose/damaged wiring. the light will go off by itself when the module senses the fault is no longer there.

You are going to need to get it scaned to find out whats wrong. a dealer or most private shops can scan the ABS for you. The free code scanning at autozone or toher parts stores only scan the PCM and will not pull ABS codes for you.
 
When my ABS light was flashing on and off.
I had my mechanic test it and it turned out that my
ABS module had internal failure and was ruined. :nonono:
Get it tested if you are lucky it might only be a speed sensor
and not your ABS module.
Good luck.