1. Remove the climate control unit.
2. Inspect for continuity between the fan switch terminals using an ohmmeter.
Mazda 6 Service Manual: Underbody Maintenance
Road chemicals and salt used for ice and snow removal and solvents used for dust
control may collect on the underbody. If not removed, they will speed up rusting
and deterioration of such underbody parts as fuel lines, frame, floor pan, and exhaust
system, even though these parts may be coated ...
Mazda 6 Service Manual: Air intake actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air intake actuator.
2. Verify that the air intake actuator operates as shown below.
If not as specified, replace the air intake actuator.
...