What signs can you look at to tell if your 1996 blazer is in 4 wheel drive?

The easiest way to tell is turn. Turn your front tires all the way in one direction and drive forward. If your blazer is in four wheel drive the tires will hop and cherp ect. Or turn your radio off and listen for a clunk when you push your 4x4 button on the dash. When engaging there will be a mild clunck. Hope this helps.