I have no idea how they work, but from your description of what happens when you hook DC to 2 of the wires it makes me think they are stepper motors. The controller moves them 1 step at a time. When working they appear to be running the same as any other motor. Stepper motors are usually used in precision positioning applications. They are however brush-less, which means they should last longer.
Sounds like overkill to me.

Paul

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84 500 SEL (307,xxx miles)