97 Silverado 4 wheel drive problem

My four wheel drive is not working, and I am not sure where to begin testing it. I think it may be and electrical issue. Is there any switches that I can check to try and stage the checks?

Do you have push button? Do the lights light up when you turn the key on? What does it do when you try to go to 4HI?

it is shift on the fly. When you place it in Four wheel drive nothing happens, no lights, and it doesn't engage.

im haveing the problem, does your truck shift on the floor or by push button. mines on the floor so i now everything up to the front axle is working, there is a sencer in the axle the turns on you automatic hubs so that could be problem to