i have a problem with the abs sistem,abslight is on and rear brakes are not work on 1993 Nissan Altima

this happen like a year ago,and ever sence still the same,what could be.

Asked by for the 1993 Nissan Altima
ABS is just like automatic breaking system you can still drive if its not working it goes back to reg. brakes when abs is off get your rear braks ck. though if there not working