GM-GMC: light problem, door switches, dash switch

Question
i have a 96 silverado when doors are open the inside dose not come on, it works when i push
upward the light switch would it be a ground wire
if so where can i find it.when the key is on the buzz comes on but no light.

        thank you hope u can help.

Answer
Most dome light circuits work with power going to the light and the other connection going to the door switches and dash switch.
In other words, the door switches work by providing a ground for the power that is supplied to the dome light.
You likely have a wiring problem at the light fixture or just beyond it where there wires going to the door switches attach.
It will not be easy to find the problem and, if the wires run in the headliner, you risk tearing it up to cure the problem.
Unless you are very mechanically and electrically qualified, this job is best handled by someone who specializes in vehicle electrical systems.
The cheapest way to fix the problem may actually be running new wires from the door switches to the dome light.