02 3.5 , 5 speed. The car had a blown head gasket ( was running) swapped the motor with one out of I35 , everything went back together fine but the 120amp fuse by the battery blows when I try and start it. Doesnt do it with key on just when I try and start it. Had starter checked it's fine, disconnected the alt and it still did it. Checked with ohm meter the alt wire and starter wire , they checked good. Ripped the harness off and couldn't find any broken wires. What am I missing?