Is your dash light dimmer turned all the way counter clockwise? If not then one of the door switches is probably bad.
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NO , Not from the factory.
Yes it is. There is a fuse for it under the hood.
You left some wires unplugged.
About the only thing they have in common is the headlight switch. Have it checked out.
It is usually wired in with the radio or the courtesy/dome lights.
Probably because the circuit board for the bulbs is rusted out at the bottom
1989 chevy 5.7
Be sure that the dash light dimmer control is not turned off and check the fuses.
check your interior or instrument panel lights fuse, they usually are all connected and when the fuse blows they all go.
The dash illumination dimmer switch is shut off or broken.
What about it?