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: Headlight bulb removal/installation
Low-beam
Halogen type
1. Disconnect the negative battery cable.
2. Disconnect the front combination light. (See FRONT COMBINATION LIGHT
REMOVAL/INSTALLATION)
3. Remove in the order indicated in the table.
Caution
A halogen bulb generates extremely high heat when it is used. If
the ...
Mazda 6 Service Manual: Vehicle speedometer sensor (vss) removal/installation
Caution
Water or foreign objects entering the connector can cause a poor
connection or corrosion. Be sure not to drop water or foreign objects on the
connector when disconnecting it.
If foreign materials are stuck to the VSS, disturbance by magnetic
flux can cause sensor output to be ...