It's hard to say if you actually were able to spin the blower. You can have DMM set to Ω also to see if the reading changes. I never took that motor apart to know the brush/commutator configuration but I'm pretty sure it's a common permanent magnet DC brushed motor.

At end of life it's very common for a winding to become detached from the commutator bar and gives you a dead spot. The goal is to get the motor to turn even a litte off the dead spot.

If the outside air vent is open just driving can freewheel some blowers add well as using shop vac air from below the outside air intake filter.

On some cars you can see the squirrel cage from under the hood with the intake filters removed. I don't remember if e53 is included.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)