Every time you turn the key in the ignition, your car’s starter motor gets to work. With a brief voltage from the battery it turns the engine’s ring gear, and that first push cranks the engine and starts ignition. Starter motors only have to run momentarily, so replacements are rare, but they can still happen. Most starter motors fail due to a dead or a failing relay. When it starts to fail, you can tell as it becomes slow to respond or makes loud noises during ignition. Catching an impending failure early can save you from being stuck on the roadside.