Continuity mistake: When the Iron Giant and Howgarth meet for the second time, they both sit down, and you can see that both the Giants hands are flat on the floor, then the Giant produces the electricity shut off switch from one of his hands even though both his hands were previously empty.
Suggested correction: When the Giant crouches down to Hogarth, his right hand is in a fist, and it stays that way as he is sitting down. The switch was absolutely in his hand the whole time.