94 Econoline E150 RABS Control Module Location

Where is this darn thing? We have replaced the sensor in the rear differential, but no help. The ABS lamp comes on unpredictably. Need some help folks. Can I scan this thing with an OBD2 scanner, or am I going to have to go the flashing light route? The Haynes manual lists three different locations for this thing, all which have proven to be wrong so far. Two dealerships have failed to give me accurate advice so far. It's time to turn to the folks that have been there, done that.

:banghead: :runaround:

Thanks for your help in advance.