When I say to jumper the blu wire to ground, I am not saying to unplug that wire and take it to ground. You place a jumper on that wire and ground the jumper. That by-passes the Reg.
If the fan does not turn when you do that, then test the red wire for 12v at the BM.
If it still does not work, spin the fan blades at the same time .
Grounding the blu wire is the same as bringing 12V direct to the fan motor ..if NO, then the BM is faulty.

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A Dalton