I've got a junked Ford auto instrument panel. It has 6 actuators for the tach, speed, fuel, etc. Identical 1" X 1-1/8" X 1/2" white plastic modules with four wires. Inside is a little (for lack of a better word) geared down stepper motor.
It might be a bipolar stepper except the two identical 170 ohm coils have a common third pole (in the magnetic circuit). The coils are set in a 90 degree "V" configuration. Three double gears to turn the (1/16" X 1/2") output shaft.
It is very easy to take apart and reassemble. .
The rotor appears to be a permanent magnet type with at least four (probably more like 8) poles. Rotation is limited to 270 degrees with a mechanical stop on the output shaft's gear.
Anyone know how they work and what it takes to drive one?