the abs light just came on and will not go out

Those lights being on indicate that the computer has sensed a malfunction and stored a trouble code. Reading the codes is the proper way to approach this but judging by the symptoms, you likely have a bad speed sensor in the top of the differential.

Thank you for your reply. Is this something I could repair myself? Special tools etc. What kind of scanner should I get.

Yes, it's very simple, just held in by one bolt.