I have 2003 tahoe, was running fine and next day wouldn't start. Accessories, dash lights up, but when turn to start and nothing. No click nothing, it's like when you turn on all power is cut off. You can't even tell that you turn the key to the on position. Checked starter, battery, fuses, relays, changed ignition switch, tested neutral safety switch,tried all the tricks found on the internet with the key and gear shift. I'm desperate and need help.