Dual A/C Control Does Not Operate [Full-Auto Air Conditioner]: Notes

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DUAL A/C CONTROL DOES NOT OPERATE (FULL-AUTO AIR CONDITIONER) - DESCRIPTION & POSSIBLE CAUSE

DESCRIPTION	Driver or passenger side temperature control dial does not operate individually Temperature control operates normally except for dual A/C control function
POSSIBLE CAUSE	Air mix door malfunction (driver or passenger-side) Air mix actuator malfunction (driver or passenger-side) Open or short circuit in wiring or poor connection between climate control unit and air mix actuator (driver or passenger-side) Climate control unit malfunction

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 malfunctions. If there is a problem, inspect to make sure connectors, terminals and wiring harness are connected correctly and undamaged.