Need help w 07 century on lights

When I turned low beam lights on while driving on highway..All the dash lights and utility lights cut off but when I turned high beam on, all the lights come on as normal even if I don't turned headlights on, light and utility lights work.
It just that every time when I cruised at night w low beam, all the lights on dash and trailer lights cut off.
Anyone knows what's the problem? If I'm at stop light or go less than 10mph, it works fine w low beam lights

 

Thank you so much for the tips. I got it fixed. Found out passenger headlight harness was hitting on metal frame and that's why it must be shortened out.