1991 Ranger RABS

[jackrussell]

I am still looking for a solution to a problem with the ABS light. It stays on any time the ignition is on. (This truck has ABS on rear axle only - RABS)
I can tell that the ABS does not work because the brakes will lock up and squeal one of the rear brakes on a hard brake application. The brakes seem to work fine except for the lack of RABS.
The connector to the speed sensor located on top of the rear axle housing is connected and appears to be clean. I did not pull the sensor out of the housing. Is the sensor itself likely to be bad?
Can anyone tell me where the antilock brake valve assembly is located on the '91 Ranger? My Haynes manual shows a picture inside the rear frame rail, but I can't find it.
Thanks for your input!

 

[4wheeltom]

The sensor it self is most likely bad, it might also need to be cleaned, the part inside of the diff not the connector. The valve is located on the driver side frame rail near the fuel filter.

 

[jd4242]

Its in the frame rail and 90% its that..try flushing the system with new fluid and get it to lock up..some tapping on it may get it to work..they rust from moisture in old fluid.