1. Inspect for continuity between the audio amplifier connector terminals and woofer connector terminals using an ohmmeter.
2. Verify that there is battery positive voltage at the woofer connector terminal A (4SD) or C (5HB) using a voltmeter.
3. Inspect continuity between the woofer connector terminal B and body ground using an ohmmeter.
Mazda 6 Service Manual: Location index
INTAKE-AIR SYSTEM
FUEL SYSTEM
Engine Room Side
Fuel tank side
EMISSION SYSTEM
Engine room side
CONTROL SYSTEM
...
Mazda 6 Service Manual: Washer Fluid
Inspecting Washer Fluid Level
WARNING
Use only windshield washer fluid or plain water in the reservoir:
Using radiator antifreeze as washer fluid is dangerous. If sprayed on the windshield,
it will dirty the windshield, affect your visibility, and could result in an accident.
Using Washer Flu ...