Check all the ground connections from the battery to to engine block and body. check all the fuses in the box next to the battery and the one on the passenger kick panel by the side of the floor board. make sure the battery terminal cables are in good continuity with the battery. if that checks out good, turn the ignition to the run position(not start), with a helper watching the gauges for any activities, go to the fuse box next to the battery and wiggle the wires and harness slowly to see if theres a loose connection on the power distribution box.