Recently got an 06 M35x and it has.. a few faults
The most egregious though is that there is no sound from the driver door. There is sound from the rear and from the seats.
I believe it is the 14 speaker system because it has the in seat speakers.
Not sure where to diagnose. Should I be looking at the amp first, the HU, the door wiring, etc. Would appreciate some guidance on this.

Most likely cause is either failed wiring, a loose connector or a failed speaker in the door. The driver door is the most frequently opened and closed and each time you open and close it you flex the copper wire going to the speaker. Copper, while flexible, eventually can crack and break. I used to maintain scanning systems for papermills. The scanners move back and forth across the paper during the manufacturing process about once per minute. Even with the very best copper cabling - usually Gore, one of the many wires would break down and we would have to replace the entire cable bundle - usually around once each year. The inside door covers on these cars are actually pretty easy to remove and get inside - it takes about 10 minutes or less. An easy way to test if the speaker is good is to use a battery with a wire on the positive and negative contacts and to tap the speaker single input points. It should make a little pop without a scratching sound if the speaker is good.

So start by taking off the door panel?
I was thinking about flipping the connectors on the amp to test to see if the amp is the source, but I havent been able to find anything about which connector is for what.

You can test the speakers using the center stack controls. There is a self diagnostic test in the options.


- Start Engine - Turn OFF the Audio system- Push and hold the SETTING button while you rotate the radio's VOLUME control either clockwise or counter-clockwise 30+ clicks.- You will then be put into the diagnostic mode.- Use the BACK button to get to previous screens.

NOTE:Holding down the SETTING button and rotating the volume knob a 2nd time will put the diagnostic mode into a more "detailed" state offering more options.

I tried that but couldn't get it to work, but either way I know which speakers don't work. The question is how to diagnose the why they don't work.

Realized that the amp doesn't have separate inputs and it's just the one connector. I couldn't find the pinout in the fsm. Could someone direct me?

How do I reach the connector for the door harness on the body side?