Inoperative Speakers Bad AMP?

[moose_load]

I recently bought a 2011 E90 M3 Sedan. My bad for not paying attention to the stereo when I test drove the car however I was too intoxicated wit the engine sound. The only speakers that seem to work is the tweeters and the front middle dash speaker, the subs, mids, and the rear are not working. I found a reset where you turn the headlights on I think, press and hold two buttons on the stereo and the system seems to reboot at least the screen does.. this provided no change. The door chime works, the phone works too. From doing some browsing Ive noticed this could be a sign of a bad amp? If it is it seems easy to get too assuming its located in the trunk under a plastic tray. Is there any way to easily verify this as a INOP amp? Or could it be another problem?

Thanks.

[dparm]

If you have a multimeter, it should be easy: just use the probe to check voltage on the different speaker outputs while playing some music. From there, you can start narrowing it down to the amp, the wiring, or the individual speakers themselves.

I'm sure someone on here can post up the info on which pin goes to which speaker.

[moose_load]

Thanks just pull the amp in the trunk to get access to the wiring harness and then Probe the outputs on the amp?

Is this a typical sign of a failed amp , and is the failure usually a bad solder internally on the board ?

[BPMSport]

Sounds like a bad amp or bad head unit - does the car have the enhanced premium sound system or the standard system?

[moose_load]

Enhanced Premium Sound so what's the next step in narrowing down Which of the two components to replace ?

Thanks

[dparm]

Originally Posted by moose_load

Thanks just pull the amp in the trunk to get access to the wiring harness and then Probe the outputs on the amp?

Is this a typical sign of a failed amp , and is the failure usually a bad solder internally on the board ?

Yep, just disconnect the harness and start probing the appropriate output pins on the amp.

I can't comment on the specific failure, but if you're handy enough, you could pop it open and inspect for obvious signs of damage (leaking caps, broken solder, etc). Not sure how easily you can fix it -- might be easier to just replace the amp outright.

[BPMSport]

I've got a replacement EPS amp in stock if it turns out to be that.