1. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
2. Remove the heater core from the A/C unit.
3. Inspect for cracks, damage, and coolant leakage.
4. Inspect for bent fins.
5. Verify that the heater core inlet and outlet pipe are not distorted or damaged.
Mazda 6 Service Manual: Rear door lock actuator inspection
Door Lock Actuator
1. Disconnect the front door lock actuator connector.
2. Apply battery positive voltage to the front door lock actuator terminals
and inspect the operation of the front door lock actuator.
If not as specified, replace the front door lock actuator.
With double locking ...
Mazda 6 Service Manual: Headliner removal/installation
1. Disconnect the negative battery cable.
2. Turn the seaming welt and weatherstrip over.
3. Remove the sunroof seaming welt. (vehicles with sunroof only)
4. Remove the A-pillar trims.
5. Remove the B-pillar upper trims.
6. Remove the C-pillar trims.
7. Remove the front and rear map light. (Se ...