Connect battery positive voltage to terminal A and ground to terminal B of the blower motor and verify its operation.

Blower motor removal/installation
Resistor removal/installationMazda 6 Service Manual: No.4 air intake mode does not change
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while performing the inspection to discover
whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to make sure connectors, terminal ...
Mazda 6 Service Manual: Child-Restraint Precautions
Mazda strongly urges the use of child-restraint systems for children small enough
to use them.
You are required by law to use a child-restraint system for children in the U.S.
and Canada. Check your local and state or provincial laws for specific requirements
regarding the safety of children ...