Mazda 6 Service Manual: No.23 a/c does not work sufficiently

No.22 vibration concerns (engine)

No.24 a/c is always on or a/c compressor runs continuously

Other materials:

Mazda 6 Service Manual: AUX/USB mode
Audio can be heard from the vehicle's speakers by connecting a commerciallyavailable portable audio unit to the auxiliary jack. A commercially-available, non-impedance (3.5 ) stereo mini plug cable is required. Contact an Authorized Mazda Dealer for details. In addition, audio can be played fr ...

Mazda 6 Service Manual: Knock sensor inspection
Note Perform the following test only when directed. Resistance Inspection 1. Turn the ignition switch to LOCK. 2. Disconnect the knock sensor connector. 3. Measure the resistance between the knock sensor terminals A and B using an ohmmeter. If not as specified, replace the knock sens ...