Nora went for her Mot and failed on the interior indicator not flashing at idle (she later passed as it flashes when revved.) When driving i have noticed that it flashes at normal road speeds but stops flashing when slowing down for junctions (at around 10 mph), it will start again when engine revs are increased. The exterior indicators flash as they should. The battery is 2 years old and has no problem starting her, she also has a dynamo fitted. Does anybody know what could be causing the problem? Thanks in advance.