1. Connect the connector to the panel light control switch.
2. Connect the negative battery cable.
3. Measure the voltage at the panel light control switch using voltmeter.
4. If the value are not as specified in the Terminal Voltage List (Reference), inspect the parts under Action and related wiring harnesses.
5. If the system does not work properly even though the parts or related wiring harnesses do not have any malfunction, replace the panel light control switch.
Terminal Voltage Table (Reference)
Terminal C inspection
1. Measure the wave pattern of the terminal C on the panel light control switch using an oscilloscope.
2. Set the headlight switch to either the TNS or headlight position.
3. Set the panel light control switch to the brightest position.
4. Verify that the pattern on the screen is as shown in the figure.
5. Verify that the pattern on the screen matches the pattern shown in the figure as the panel light control switch is gradually turned to the darkest position.
Mazda 6 Service Manual: To Operate the System
The High Beam Control System (HBC) operates to switch the headlights automatically
between high and low beams after the ignition is switched ON and the headlight switch
is in the AUTO and high beam position.
The High Beam Control System (HBC) determines that it is dark based on the brightness
...
Mazda 6 Service Manual: Service cautions
HANDLING INSUFFICIENT REFRIGERANT LEVEL
If an insufficient refrigerant level is detected at troubleshooting,
do not charge (add) the refrigerant. Because an accurate amount of
refrigerant cannot be determined from the pressure indicated on the manifold
gauge, never charge the refrigeran ...