Been searching but can't find an answer. I have 94 E350 Motorhome with 4 wheel ABS and the light is on solid from key on. Is there a self diagnostic for the 4 wheel ABS? Jumping the black/orange stripe wire does not make the light flash at all. I don't have a scan tool, only an OBDII code reader. All sensors have been ohmed, cleaned and reinstalled, wheels spun and voltage measureable. Any place else to look before I buy a $400 ABS pump?