1987 Chev s10 Electrical Help

Please help!! I have an 87 Chev s10 pickup, and am having electrical which I have no clue what else to do. The rear brake lights work during the day, but once I turn on the headlights at night the brake lights do not work, the rear tail lights do not work, and the blinkers do not work, but the headlights work. Any help would be appreciated!!

check all ur wires goin to the back for cuts or any possible way they could touch teh frame