Dome light won't go off even when the doors are closed

I would think not correct. GM vehicles of that era were equipped with R.A.P(Random Auxiliary Power) it would keep certain systems on after shutting the car off.....(lights, radio, power windows) for up to 8 minutes. Unless you open the door, that would shut everything down. So if your power is staying on with doors open, most likely one or both of the relays in the RAP is bad

the button is at the door hinge by the weather seal it takes a 3/8 wrench or a socket to remove and replace,don't let the two wires touch it will blow a fuse they are about $5 at part house good luck...

one or more of the door switches are malfunctioning

This is a short on the dome lamp assembly. It is possible that the ground wire from the dome to switches is short.
remove assembly and check.

Posibly a short in the wiring from a door switch. Try each one with the rest of the doors closed until you find it. You should be able to remove the switches from the door pillars.

Check for corroded wire connector kick pad driver side clean wire try this or change the connector

The door sensors will need to be replaced. A screws can be removed and then a wire can be taken of and you then can replace the switch.

Been having a problem with the dome lights on a 99 chevy blazer. Still can't figure out what the problem is. There is a dome light overide button located under the dimmer wheel. When I push the overide button in the dome light goes off, but when I open any of the doors the dome light will not come on. When the overide button is out the dome light stays on all the time and will not turn off even though every door is closed. I checked all the pushbuttons and everything tests good. Has anyone had this problem and know how to fix it?

find out witch door sensor is grounded out and dome will go out

This is usually caused by the switches sticking in the door latches. Try spraying some WD40 in the latches and open and close the doors a bunch of times that should take care of it.