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: Lane-Change Signals and Three-Flash Turn Signal
Lane-Change Signals
Move the lever halfway toward the direction of the lane change—until the indicator
flashes— and hold it there. It will return to the off position when released.
Three-Flash Turn Signal
After releasing the turn signal lever, the turn signal indicator flashes three
times ...