2000 Silverado 2wd won't stay running.

Hello, The body harness for the rear of the truck should disconnect at a central point, disconnect it there. Once disconnected, start the truck, and make sure the connector is not touching anything. If the truck runs, you know there is probably a short to ground happening back there. If it still does the same thing, look first at the instrument cluster for a key or security warning. I'm assuming you disconnected the battery, and it may not be recognizing your key resistor.