Jumper wire
Caution

Voltmeter
is used by connecting the positive (+) probe (red lead wire) to the point where voltage will be measured and the negative (-) probe (black lead wire) to a body ground.

Ohmmeter
Caution

Connectors
Precautions before weldingMazda 6 Service Manual: Cargo compartment light switch inspection
1. Remove the liftgate lower trim. (See LIFTGATE LOWER TRIM
REMOVAL/INSTALLATION)
2. Disconnect the cargo compartment light switch connector.
3. Inspect for continuity between the cargo compartment light switch
terminals using an ohmmeter.
If not as specified, replace the liftgate lock.
...
Mazda 6 Service Manual: Warning Light and Brake Pad Wear Indicator
Warning Light
The warning light turns on when the system has a malfunction.
Refer to Warning Indication/Warning Lights
Brake Pad Wear Indicator
When the disc brake pads become worn, the built-in wear indicators contact the
disc plates. This causes a screeching noise to warn that the pads shoul ...