Help needed with abs test!!..

[speedy chris]

Ok so my abs light came on about week ago! pluged computer into it and it said o/s/f weel speed sensor so replaced with one from brakers that they said has been tested.
Fitted it today and light went off happy face, well till I took for quick drive as soon as I got off drive light came back on and didn't go off tried disconnecting checked conections started car light stays on? Thinking it might be my loom!
Can anyone tell me how to check it for broken connection with multimeter as never really used one?