There should be 2 wires going to the RHS wheel on an ABS car. The ABS sensor is fitted through the middle of the upper swivel bearing (a Railko type I think rather than a roller bearing). There is also a 3-core connection to the brake pad wear indicator which connects directly to the inner pad. If the ABS warning light is on showing a fault you can easily make up a test plug and interogate the ABS system yourself to find the fault, the instructions are in the Haynes manual (and you all thought they were c**p).
If the ABS lamp isn't showing a fault then it's more likely to be the wear indicator. Ours is also snapped off and frankly I don't really care.
Just watch for the brake warning light instead, shwowing the wear indicator inoperative of pads excessively worn.