My asd fuse keeps blowing up

I am going to assume it's fuse 12 (10A) that keeps blowing. I also assuming you have the 4.7L engine. Fuse 12 powers your Fuel Pump Relay, Auto Shutdown Relay (ASD), Powertrain Control Module (PCM), and the Transmission Control Module. You will have to isolate the circuit that is shorted to ground to correct the problem. Pull Fuse 12 out and use an ohm meter to measure resistance from the output side of the fuse to a body ground. If there is a problem, it will read something less than 1000 ohms I'd assume. When the problems fixed, it will read infinite resistance (open circuit). Remove the positive cable from the battery. While the ohm meter is hooked up, pull the fuel pump relay. If that doesn't fix it, remove the ASD relay. If that doesn't fix it, remove the C1 connector from the PCM. If that doesn't fix it, remove the connector from the TCM. If that doesn't fix it, you have a wire in the harness that is chaffed and touching the body somewhere or another wire that is grounded.