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: Intake-air system removal/installation
Warning
When the engine and intake-air system are hot, they can badly
burn. Turn off the engine and wait until they are cool before removing the
intake-air system.
Fuel vapor is hazardous. It can easily ignite, causing serious
injury and damage. Always keep sparks and flames away from ...
Mazda 6 Service Manual: Replacing Exterior Light Bulbs
Headlights (With LED headlights)
Low/High beam bulbs
The LED bulb cannot be replaced as a single unit because it is an integrated
unit.
The LED bulb has to be replaced with the unit. We recommend an Authorized Mazda
Dealer when the replacement is necessary.
Headlights (With halogen headlight ...