Left side front and rear speaker malfunctioning
 

Hello,

I need help on a problem I am experiencing with my 2015 Mazda 2.

All of a sudden, the left side front and rear speakers have stopped functioning.

I have ruled out the following causes:
1. I have checked the fuse box and ascertained that all fuses are functional by means of a multimeter.
2. In the audio settings I confirmed that the balance is set to the middle. Therefore, I concluded that this is not a software related cause.
3. My sister has the same car and I have uninstalled the head unit from my car and installed it in her car. While installed in her car, I ascertained that the output on both the left and right audio channel was functional. Therefore, I concluded that the head unit is not the cause of this problem.
4. My sister has the same car and I have uninstalled the (non-Bose) amplifier located behind the glove box and installed it in her car. While installed in her car, I ascertained that the audio signal on the left and right side was amplified properly. Therefore, I ruled out that the amplifier is not the cause of this problem.

The only logical conclusion I can come up with is that the cause of this problem is:
1. faulty wiring from the head unit to the amplifier, or;
2. faulty wiring from the amplifier to the speakers; or;
3. a faulty speaker that is messing up the whole left side channel.

I would love to hear your thoughts and suggestions on this matter, as I am in desperate need of help.

Thank you in advance.



Status update: It turned out that both door speakers were faulty. I replaced them and now everything works accordingly.