1. Disconnect the negative battery cable.
2. Remove the headlight cleaner switch. (See HEADLIGHT CLEANER SWITCH REMOVAL/INSTALLATION)
3. Inspect for continuity between the headlight cleaner switch terminals using an ohmmeter.


Headlight cleaner switch removal/installationMazda 6 Service Manual: Dtc c1955, c1956
Caution
When attaching the tester lead to the DSC HU/CM connector the SST
(49 G066 004) must be used.
Diagnostic procedure
...
Mazda 6 Service Manual: Fog Lights (Some models)
The fog lights can be turned on with the ignition switched ON and the headlights
turned on.
Use this switch to turn on the fog lights. The fog lights will improve visibility
at night and during foggy conditions.
The fog lights turn on when the fog light switch is turned to the
position and t ...