Rear door speaker

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

Connect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .)
Disconnect the rear door speaker connector. (See REAR DOOR SPEAKER REMOVAL/INSTALLATION .)
Inspect the resistance between rear door speaker terminals A and B.
Rear door speaker resistance

Without Bose®: 3.2-4.0 ohms

With Bose®: 3.24 -3.96 ohms

Courtesy of MAZDA MOTORS CORP.
- If not within the specification, replace the rear door speaker. (See REAR DOOR SPEAKER REMOVAL/INSTALLATION .)