Dome Light

I have a200 Z71 and am having problems with the dome light not coming on when I open the door. Initially I thought that it was turned off but when I pushed the dome light button the cargo lamp light came up on the message display(no cargo light came on) so I turned the dome light off. After about a minute then dome light decides to come on and when I press the button the cargo lamp message does not come on anymore when pushing the dome light button. It only does this about the first minute or less when I start the truck. Any suggestions?