Jon Wolff

I've got a 99 quattro avant with the Bose concert system (at least it says bose when I turn it on).

Neither front left speakers (driver or tweeter) produce any sound. Voltmeter on the terminals at the speakers both show 5+ volts so they are getting power. Any thoughts on what my next step in troubleshooting should be?

I doubt its the speakers since both on that side don't work, it would appear that the amp is powering them but they aren't getting any actual signal.

It isn't clear to me that the front speakers are powered by the amp in the rear. If I unplug the harness at the rear side of the amp the rear speakers and sub die but the front right speakers stay on.

Thanks guys.

OGBULLYLOCDAWG

Have you tried swapping the speakers around to rule them out as the issue(Drivers)?

jcman

The fronts and the rears are powered from the sub/amp in the right side of the trunk.

Here is some good info, but remember to start at the bottom of the first page.

nm3210

I think you might be a little confused about how speakers are powered. Speakers shouldn't ever see a constant (DC) voltage (more than 100mVDC is usually considered pretty bad), they are designed to only see an AC signal (ie. your music amplified). And that voltage will be going up and down continuously as the music changes; it should effectively be zero when there is nothing playing. So maybe you could clarify if you were measuring +5v DC or AC (but a constant AC signal implies a constant noise like a sinewave). If you were seeing a solid +5v DC voltage at the speaker terminals, there might be a problem with the amplifier circuit for that channel (and since both speakers are out it would before they are crossed-over).

But as all things speakers go: swap drivers around, wiggle wires, etc. to see if you can get anything working.

Jon Wolff

I was seeing +5 DC . I'll test again with my meter in AC mode next time I take things apart as well as use some test clips to wire in to a speaker from a different car.

One thing I noticed which I though was odd, when I unplugged the harness on the amp/sub in the back right, only rear speakers stoped. The front right speaker which does work kept playing. The amp/sub is a blaupunkt unit, no bose labeling that I could see, however the car does have the 8 speaker setup and the stereo is in bose mode.....

Thoughts? (and thanks for the help)

jcman

If you have two sub woof's its a Bose.
If you have one woof then this pdf can guide you.

Just Me

If you are seeing +5V DC you have a problem. And the voice coils are likely shot too.

If you are seeing (average) 5V AC - its at 50% of full power and your ears should be bleeding, and the amp clipping.

Something is not adding up.

Grant

nm3210

Even non-Bose have 8 speakers + sub woofer (I have two '99 A6's, one with Bose and one without) and it's easy to change the actual radio between Bose and non-Bose - it's just a switch in the encoding and takes a few seconds. Do you see Bose anywhere else in the car? It is usually plastered on every lower speaker grill pretty obviously (and as mentioned is really obvious on the subwoofer). This might just be a problem of the radio being coded wrong....! When I was swapping radios between my Bose and non-Bose cars (for a minor reason and more curiosity) I had your same problem of the front left speakers not working at all before I changed the encoding properly.

Just Me

Still, if you saw AC that means there is a big problem. Amp putting out DC (bad); DC on the voice-coil (maybe burned up by now), ro some sort of leakage from a DC power wire. Confusing to say the least. Music is pure AC, with nominal 0 vdc

Grant

jcman

Bose systems have ten total and non-Bose have nine.

You're probably right on the radio coding too for it does allocate passive and non-passive around the amp sources and the Bose radio display code is just eye candy,