99 Taurus Abs light was intermittent, now on

I have a 1999 Taurus and the Abs light started to come on mostly in City driving. It would always take a half an hour or so, sometimes, it wouldn't come on for days. So I took it to the dealer and now it's on as soon as you start the car. They say I need a ABS module because they can't communicate with it and , Oh yeah, they "Fixed" some of my wiring. I can't find what they fixed, so I'm going back and ask them why they made the problem worse. Maybe I can un fix it. Thanks