1993 Buick Roadmaster Owner's Manual - Page 270

. . ,. , , . . , ... Unskrew .tht$wingnut. From outside the vehicle,, carefully pull the taillight assembly away from the body. Press thebulb housing release lever and turn the housing 1/4.turn counter-clockwise (to the left) to remove it.. To remove the bulb, push in and rotateit it counterclockwise(to the left). Reverse all the stepsto reassemble the taillight housing.