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: Curtain Air Bags
The curtain air bags are mounted in the front and rear window pillars, and the
roof edge along both sides.
When the air bag crash sensors detect a side impact of greater than moderate
force, the curtain air bag inflates quickly and helps to reduce injury mainly to
the rear outboard passenger' ...
Mazda 6 Service Manual: Door lock timer unit inspection
1. Measure the voltage at the door lock timer unit terminals (other than
terminal 1E and 2W) as indicated below.
If not as specified, inspect the parts listed under Action.
2. Disconnect the negative battery cable.
3. Disconnect the door lock timer unit connector and inspect for continuity ...