Vauxhall Vectra headlights flashing when driving

When im driving during the day my headlights are flashing on and off and the headlight indicator on the dash is also flashing, this is going on whilst ma headlights are switched off, one of the relays behind the glove compartment is clicking like crazy and the lights behind the stereo n dashboard are flashing too, I've recently changed the alternator and timing belt and this problem has arisen since then, I know of another vectra with the same problem which has just changed the alternator and timing belt, please help