i have a 2003 tahoe lt 4wd 5.3, 155k, just bought it, went to start and noticed no cluster lights working and gauges not moving, turns over but will not start, had flat bedded down to service shop, unloaded truck and it started, drove a 4 miles and parked it at shop, ran fine, next morning, exact same thing, no cluster lights, no start, change ignition switch, not the the slot where the key goes but the square box where the wires plug in..still no start..any ideas?!