There is a 175 amp fuse on the firewall next to the battery. This fuse controls all electrical to the truck and is most likely the problem. You can check it with a test light. Connect the ground lead on the test light to the negative post on the battery which is the post closest to the firewall. Then touch the positive lead of the light to the positive lead on the battery to see if your light is working and the battery has power. If the light comes on, then touch the positive lead of the light to the 175 amp fuse. You need to remove the plastic cover off the fuse, it just pulls off. First touch the side closest to the battery, it should light up, next touch the side away from the battery. If the light does not light up, the fuse is blown.