hayes lemmerz controller problem?

Hi folks - has anyone had their brake lights mysteriously come on and stay on until the fuse is removed from the brake controller power supply circuit? We have a fairly new Endeavour model in our 80 series and the led code says OC (open circuit), but I would have expected the fuse to blow if there was a real short somewhere. I haven't checked it all properly yet but was wondering if this was a symptom of a problem someone else has seen before. Thanks, Nige.