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: Variable air duct (vad) control solenoid valve inspection (l3)
1. Remove the VAD control solenoid valve. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
2. Inspect airflow between the ports under the following conditions.
If not as specified, replace the VAD control solenoid valve.
If as specified, carry out the Circuit Open/Short Inspection.
Circ ...
Mazda 6 Service Manual: Front door glass removal/installation
1. Operate the front door glass so that the distance from the top of the
front door glass to the upper part of the rear beltline molding is 210 mm
{8.3 in}.
2. Disconnect the negative battery cable.
3. Remove the front door trim.
4. Remove the hole cover.
5. Remove the screws.
6. Insert ...