I fixed the one on my '89 230TE as follows.
Open up the aluminium casing by releasing the locking tangs and carefully remove the printed circuit board inside. With a hot soldering iron carefully melt each joint on the pcb and allow to cool again.
Replace the pcb and secure inside the casing by carefully bending the tangs back in.
Provided you are carefull and know what you are doing with electronics there is nothing to loose, never saw that ABS light again (except during ignition on self test) for the 3 years I had the car after that. Before it used to come on and off almost at random, always associated with poor idling and reluctant starting.
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)