Vehicles have various electrical parts. To protect the parts from excessive current generated when welding, be sure to perform the following procedure.
1. Turn the ignition switch to the LOCK position.
2. Disconnect the battery cables.

3. Securely connect the welding machine to the ground near the welding area.
4. Cover the peripheral parts of the welding area to protect them from weld spatter.

Electrical troubleshooting tools
Jacking positions ,vehicle lift (2 supports),safety stands (rigid rack)
positionsMazda 6 Service Manual: Dtc table
DTCs are common for present and past malfunction diagnosis.
Note
When DTCs not shown in the DTC table are displayed, replace
the SAS unit.
If the air bag system warning light does not illuminate or
remains illuminated when the ignition switch is turned to ON position,
i ...
Mazda 6 Service Manual: Combination switch removal/installation
1. Disconnect the negative battery cable.
2. Remove the driver-side air bag module. (See DRIVER-SIDE AIR BAG MODULE
REMOVAL/INSTALLATION.)
3. Remove the steering wheel. (See STEERING WHEEL AND COLUMN
REMOVAL/INSTALLATION.)
4. Remove the column cover. (See COLUMN COVER REMOVAL/INSTALLATION)
5 ...