Ditch the harness, problem is they don't 'kick in' till the dog has already pulled with its front legs. You put a harness on a dog or a horse so it CAN pull, i.e. a sledge or a cart.
Use a half check collar (sometimes called a combi collar)which give you some control of the dog, and check the dog as it pulls forward (very light jerk towards you) giving a command heel or similar word, and the half check collar will tighten a little and then release as the dog is in the correct place. It is crucial that the collar is adjusted to fit the dog, with the chain portion forming a triangle when you put the slightest pressure on it, otherwise it will not work and release properly and your dog will just keep on pulling. The chain must form part of the circle of the collar, the webbing or leather must not meet.



