1. Disconnect the negative battery cable.
2. Remove the dashboard. (See DASHBOARD REMOVAL/INSTALLATION.)
3. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
4. Remove the blower unit.

5. Install in the reverse order of removal.
Basic system
Blower unit disassembly/assemblyMazda 6 Service Manual: No.1 while vehicle is in reverse, vehicle locator mark goes forward
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while doing the inspection to discover whether
poor contact points are the cause of any intermittent malfunction. If there
is a problem, check to make sure connectors, terminals and wiri ...
Mazda 6 Service Manual: Instrument cluster removal/installation
Caution
When replacing the instrument cluster, the configuration procedure must be
performed before removing the instrument cluster. If the configuration procedure
is not performed before removing the instrument cluster, it is possible that the
instrument cluster will not operate normally. ...