If the light will work with the pull chain, we know there is power to the light. You said you wired directly to the light with the black and white, with a switch interupting the black. This is wired correctly. Are you sure your leaving the pull chain in the on position,then operating the switch.Other than this,I don't have a clue Carl is right, the ground has no function concerning the light. Let us know any results,Ron J.