Looks like I'll have pay :smilie_re: Phil a visit for the oscilloscope for a definitive answer as I have virtually same problem, ABS crunching but no lights on so T4 doesn't show anything.

Get a male and female ABS plug and socket, a capacitor and a piezo earpiece and try that first. I described the circuit a few years ago, it is much easier to listen for clicks and watch the marks on the tyre, than watch a meter and the marks at the same time ;).

Just spent an hour reading all these posts and learnt some interesting stuff. Currently in the process of changing a front sensor (the pscan told me it was 'open circuit') and certainly a new replacement sensor passed the static test. However, with prior knowledge of these posts I would have checked the wiring before removing the defective? sensor.
Now to fit it and hope that drilling out the old one and poking about has not damaged the traluctor ring.
Must also trawl the local yards so I can make up a test rig for the future. One of the other 75s has the slow speed ABS judder which original correspondant Larry had so much trouble in finding.