I've had my 2005 limited roadster for a couple of months now. When I got it I had no audio out of the right side (either door or rear speaker). After some troubleshooting I discovered that my head unit was outputting DC on the right side, so I picked up a Blaupunkt St. Louis of Ebay and installed it. Everything worked great for a week -- sound was fine out of the right side. But then it started cutting in and out on the right side again. This time it would emit some high pitched screeches and pops out of those speakers. When a fan would turn on in the engine, it would sound like a dentist drill or something like that.

So I figured that the original head unit had damaged the factory amplifier because of the DC output, so I just picked up a replacement amplifier off Ebay. After installing the replacement factory amp, I'm still having the same problem -- the right side cuts out with some high pitched screetching and popping. So I still have a problem with a new head unit and a new factory amp.

I've ohmed out speaker connections and they seem fine. Could this be a problem with the speaker? When the sound goes out on the right side, it goes out in both the door speaker and the rear speaker. That seems like a problem with wiring before the front/rear signals even get split going into the factory amp. What else should I look at to troubleshoot?

Am I risking damaging the new Blaupunkt head unit and amplifier with this problem?

 

Well if the head unit and the amp have been swapped out and the problem stays you are looking at what you left behind. I know - statement of the obvious. But what does that represent?

The wiring from the head unit to the amp, and the amp to the speakers. The speakers (total of six to look at).

It might turn out that the old head unit and old amp are OK so don't pitch them yet.

Take a look at the plugs at the amp and see if any of the pinouts are bent, broken, corroded, etc. After that, it might mean going into the speakers.

The factory service manual has a section on troubleshooting the factory sound system - see if it has any symptoms described that match yours.

Another approach is to try running speaker level outputs from your new head unit (if you have them, could be RCA outputs) directly to some speakers (not the ones in the car).

That eliminates the factory amp and speakers, and the wiring harness completely. See if the same problems happen. If so, it might be a bad ground or ?? If it doesn't happen with this setup, then you're probably looking at swapping out a bad factory speaker.

It's not that likely that the harness is bad especially if you didn't cut into it.