1. Remove the climate control unit.
2. Inspect for continuity between the fan switch terminals using an ohmmeter.


Climate control unit inspection
Defroster switch inspectionMazda 6 Service Manual: Instrument cluster configuration
1. Connect the SST (WDS or equivalent) to the DLC-2.
2. Input vehicle information following the directions on the screen.
3. Select Module programming.
4. Select Programmable module installation.
5. Select the following items and perform procedures according to directions
on the screen.
...
Mazda 6 Service Manual: Trailing link removal/installation
Caution
Performing the following procedures without first removing the ABS
wheel-speed sensor may possibly cause an open circuit in the harness if it
is pulled by mistake. Before performing the following procedures, remove the
ABS wheel-speed sensor (axle side) and fix it to an appropri ...