Vauxhall Astra - Dashboard Digital Display

[gringo123]

On the dashboard of my Vaux Astra there are 2 digital display units. one shows the time, radio station details, etc. and the other is the mileage counter.
Recently I have noticed that this display goes off as soon as I turn on the headlights. Clearly there is something in the headlight circuit that breaks the circuit controlling the dashboard display. Does anyone have any suggestions?

 

[wingcoax]

Does it happen with side lights or just headlights? If wth side lights check your dimmer knob on the dash, it also affects your dash lighting.