There are 4 wires at the blower regulator.
Start testing there for command voltages.

Big red wire is power(12V) from the battery (not fused)
Big black wire is ground.
One of the smaller wires should have 12V with the key & a/c controller on.
The last small wire can have from 1V to 7V dependand on the blower knob position.

If you have those voltage readings & the blower is INOP...the regulator IS the problem.

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