The door jamb or courtesy light switch is the push button style switch that turns on the dome light when the doors are opened. Sold each - two required per truck. The door jamb or courtesy light switch is the push button style switch that turns on the dome light when the doors are opened. Sold each - two required per truck. Compatible with 1970-1984 Chevrolet/GMC C/K Series Truck, Blazer/Jimmy & Suburban Compatible with 1970-1984 Chevrolet/GMC C/K Series Truck, Blazer/Jimmy & Suburban