82 supreme headlights question

i just got a 1982 cutlass supreme. at first, only the brights worked, and the interior lights didnt work. i messed around with the stereo a bit, and then the interior lights came on, and the regular light were working. now, the brights only work, but the interior lights still work. so what would cause the lights to go from brights, to regular lights, then back to brights? could it be a loose wire touching or something?