I'm having problems with my Vauxhall Monterey (rebadged Isuzu Trooper). The ABS system is kicking in during normal braking. The brake pedal goes firm, judders, and I am unable to stop the vehicle smoothly or quickly. The ABS light is working but does not light up to indicate a fault. If I remove the fuse and disable the ABS system then the brakes work fine (without ABS control of course!). Anyone have any clues as to where to start diagnosing this fault?

i would check around for a parts store in your area that has an ABS system scanner...