iMac G4 Fan swap - not spinning up after replacement

[macminitosh]

I was working on replacing the loud and old fan on my iMac G4. I cut off the connector of the old fan, and determined the polarity as follows:

(Cable color on iMac → corresponding cable on replacement fan (Arctic F9):

 

Black → striped black cable

Red → middle cable

Yellow → outer black cable (not striped)

 

When connecting the old fan like this to a USB adapter, it spins up. After Installing the new fan in the iMac, the fan doesn‘t spin up and isn‘t „detected“ by the OS (10.4.11). How can i go about testing if the polarity of my cables is correct? I do have a multimeter available, i just don‘t know what to measure. Or maybe someone here knows the correct layout of the cables?