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: Disconnection of the negative battery cable
Before beginning any work, turn the ignition switch to LOCK position,
then disconnect the negative battery cable and wait for more than 1 minute
to allow the backup power supply of the SAS unit to deplete its stored
power. Disconnecting the battery cable will delete the memories of the
...
Mazda 6 Service Manual: No.4 air intake mode does not change
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while performing the inspection to discover
whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to make sure connectors, terminal ...