Inner cabin fan on 07 pontiac vibe driving me nuts

Just recently I had my cabin air filter sucked down into the cabin fan which was found out when the fan knob had no effect on air flow. Air filter was pulled out, I was charged $90 and off I went with working cabin fan.

Now 2 months later, again my fan is unresponsive from air level knob. All dash items work fine. This time around air filter is in place. The fan doesnt turn on with the knob from a dead start. The kicker is with vents open from outside, air flow seems to cause the fan to move which in turn then causes the knob to function at all levels…till I turn off the car. Then dead until I get a good air flow through vents.

Cant spare fund so I wish to do some troubleshooting myself this time around and heard good things about you lot. Any ideas or guidance?

Can you just clearly state what the problem is? a simple inop fan?. The info about the cabin filter and the info about the effect of outside air flow have confused me.

The air filter hitting the fan has damaged or misaligned the fan and motor. It could be just a piece of debris still in there. It might be misaligned bearings causing the fan to get stuck and the motor doesn’t have enough torque to get going on its own. There could also be a loose electrical connection or an issue with the motor brushes and commutator. The thing to do is remove and inspect the motor and fan.