BMW 328i coupe had the ABS light on the dash one day and needed a WOF.
Checked all the sensors, fuses, relay boxes. All seemed ok. Took to BMW to get plugged in, came back with faulty ABS control unit (inlet valve). BMW offered to replace at $1500 + labour + gst. No thanks. They also offered the services of a bloke somewhere in the North Island that repairs them for around $700. I decided it could be done on the cheap.
Had a hunt on the net, found out that BMW used some pretty shitty cellophane type wiring for the control unit to link up the solenoids, over a matter of time, rather than use, it breaks down and it throws the light up.
So off to the the old mans place, with $0.50 worth of wiring, we crack out the control unit, rewire it, put it back in, bleed the brakes. No more light and WOF the following day