Remove the regulator handle clip using a rag as shown.

Inner handle removal/installation
Regulator handle installationMazda 6 Service Manual: Electrical parts
Battery cable
Before disconnecting connectors or removing electrical parts, disconnect
the negative battery cable.
Wiring Harness
To remove the wiring harness from the clip in the
engine room, pry up the hook of the clip using a
flathead screwdriver.
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Mazda 6 Service Manual: Front and rear fog light switch inspection
Light switch LH side
1. Remove the light switch. (See LIGHT SWITCH REMOVAL/INSTALLATION.)
2. Inspect for continuity between the light switch terminals using an
ohmmeter.
If not as specified, replace the light switch.
Light switch RH side
1. Remove the light switch. (See LIGHT SWITCH ...