can anyone help,my dishwasher will now only work on pre-rinse cycle,when this cycle has finished it bleeps 8 times as normal but when i put it on any of the remaining 5 settings it will pre-wash again as it should but then bleeps 25 to 30 times,stops and i get either pre-wash + wash lights on or pre-wash + rinse lights on,please can anyone shed some light on this problem,many thanks for reading this