I need some help I just got my mom's 96 Altima with 400k miles on it. Still runs fine but the instrument back lights and shift indicator lights are out. I checked all fuses and it is happening with two different clusters. It does have a aftermarket stereo so I checked the illumination wires and they are connected. Can someone give me a list of other things to check out. Is there a way to test the dimmer or do I need to just buy one and see.