2006 F-53 Stripped Chassis. Recently changed all rotors, pads, calipers. No ABS light on prior to job. One wheel done at a time so no possibility of parts mix-up. Front rotor has ABS ring. Rear does not.
Front and Rear have ABS sensors. No sensor on rear axle (DANA S150S) so I must have 4 channel system (plus why wire sensors to wheels if not used?). Again, rear rotors had no ABS ring.

I can't figure why ABS light was not on before job started. How can ABS work if rear sensors have no ring?

Parts selection is a mess. I got part number from fordparts.com. There are many choices listed on rockauto but I got my part numbers from fordparts.com. Some choices show ABS rings, some do not. It's all over the place.

I examined parts when replacing to make sure they were exact match.

I didn't know squat about ABS when I did the job but now that the light is on, I am finding this strange situation with no ABS ring on rear hub. I am second owner but I doesn't appear they were changed from original (bought with 30K miles) but who knows.

New code reader on the way to try and read code. It's only the ABS light. Brake system works fine. I disconnected battery and took another drive but ABS light stays on.

Any thoughts or ideas? Thanks.

 

Could be the brake switch