1. Connect the connector to the running light unit.
2. Connect the negative battery cable.
3. Measure the voltage at the running light unit 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 running light unit.
Terminal Voltage List (Reference)



Running light unit removal/installationMazda 6 Service Manual: Snow Tires
Use snow tires on all four wheels
Do not go faster than 120 km/h (75 mph) while driving with snow tires. Inflate
snow tires 30 kPa (0.3 kgf/cm2, 4.3 psi) more than recommended on the tire pressure
label (driver's door frame), but never more than the maximum cold-tire pressure
shown on the tir ...
Mazda 6 Service Manual: Climate control unit disassembly/assembly
1. Disassemble in the order indicated in the table.
2. Assemble in the reverse order of disassembly.
Wire Disassembly Note
Disassemble the wires in the shown in the figure.
Wire Assembly Note
Assemble the wires to the position as shown in the figure.
...