Dome light will not come on when the door is opened. Light comes on only with switch on my 2005 Chevy Silverado

SOURCE: no dome light when passenger door open

Since the passenger door doesn't get used as much as the drivers door, check to see if the switch is not just stuck. It is a little button with a spring that opens up and turns the light on. It is located on the hinge area of the door and when the door closes it shuts off the switch, if it is not stuck then I would suspect said switch.

SOURCE: dome light and door lights don't come on when open

try looking for the door switch it is usually mounted on the inner door frame sometimes they stick when older and will not come out all the way to activate the light

SOURCE: 1999 Chev Silverado Door Light Switch

the actuator for the dome light is actually located inside the lock mechanism. Have you checked to make sure the dome light override button is in the out position?

SOURCE: Chevy silverado 1500 truck, year

sounds like water got into the switch.

SOURCE: dome light does'nt come on when door is open. there is not a switch to move from door,on or off.

Make sure the bulb is good. Does the passenger door opening turn the light on ?
Also check the fuse for the dome light. It's in the fuse box on driver's side. Fuse location will be in your owner's manual.
If the bulb and fuse are good, then the problem is likely a bad door switch. It needs replacing.. Good luck.