Testing the speedo drive

[FFMan]

So the speedo on my rover gearbox Griff has stopped working.

So i plan to drop the exhaust and get the sensor out, check the wiring etc.

If i turn the ignition on and spin the sensor (by hand or with a drill), should the speedo register without the engine running ?

It feels like it should work, as a stalled car rolling down hill would show speed on the speedo.

just wondered if anyone can confirm ?

thanks