Jump some wires to the blower motor (disconnect harness) and see if it spins.
If it does, the issue is likely the blower motor speed controller, and/or it's wiring.
You can also try putting the fan on full high, then tapping the up button again. It will click on the high speed relay in the BMSC to bypass the transistor. if the fan comes on, it's fine and the issue is still the BMSC (but wiring is probably ok)