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.

Panel light control switch removal/installation
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COOLING SYSTEM SERVICE WARNINGS
Warning
Never remove the radiator cap or loosen the radiator drain plug
while the engine is running, or when the engine and radiator are hot.
Scalding coolant and steam may shoot out and cause serious injury. It may
also damage the engine and cooling sys ...
Mazda 6 Service Manual: Fuel pump unit inspection
Caution
It is normal to hear the fuel pump operating when the ignition
switch is turned to the ON position.
Note
To improve startability, the fuel pump control operates the fuel
pump unit when the ignition switch is turned to the ON position. Due to
this, fuel pressure is rapidly ...