Chevrolet 4500 HD 2023 Manual page 79

78 Lighting
Rear Light (Crew Cab Model Only)
The dome light operates regardless of the
engine control switch position. The switch
has three positions.
ON : The light stays on regardless of the
doors being open or closed.
OFF : The light stays off regardless of the
doors being open or closed.
Between ON and OFF, the light comes on
when the driver's door is opened.