2007 XC70 Audio Problem HU650

[duanew]

I’m having a problem with the audio my 2007 XC70. It started out with the front left speaker cracking very loudly. The only thing extra that is connected to the radio is a Motorola HF 850 Bluetooth hands-free kit. This was installed by the previous owner. The other day the left front speaker started cracking loudly while we were going down the road. The radio last turned off and the noise continued. Later the sound in the front right started cracking as well. This was an intermittent a noise that did not seem connected to bumps or anything. I believed that it might be the amplifier.

I’ve heard that some of the XC series do not have an amplifier. I’ve looked under both seats and did not find it there attached to the floor. I have removed the number 11 fuse and that did not shut off the music. This led me to conclude that it was the head unit. Because the number 11 fuse did not turn off the music, I believed that the car did not have the extra amplifier. I ordered a used HU 650 off eBay and installed it. This did not solve my problem. I currently have the music faded to the rear but this is not a good solution because it sounds terrible. There are still sounds coming out of the front speakers but they are garbled and terrible.

I have searched and could not find references where the amplifier is. I’ll probably replace it with a small aftermarket unit if possible. I would like to keep the stock head unit to retain the back up sensors. I would appreciate your direction and where to look next for my problem.

[hoonk]

1. The only thing extra connected is a Motorola HF 850 Bluetooth hands-free kit.
2. The other day the left front speaker started cracking loudly while we were going down the road.
3. The radio was turned off and the noise continued.
4. Later the sound in the front right started cracking as well.



i have searched and could not find references where the amplifier is.

Does the motorola bluetooth kit use the (front) speakers in the car? If so i would disconnect it and see what happens.

If you have an external amp it is located on the floor under the middle of the passenger seat, the wiring to it is usually visible - there are 4 twisted pairs of wires (speaker wires) and a silver signal cable going to the amp.

[JRL]

No external amp on 650s, you can always install one but that does not to be your problem!

[duanew]

Does the motorola bluetooth kit use the (front) speakers in the car? If so i would disconnect it and see what happens.

This could be the problem. I will give it a try. The only thing that makes me wonder is that the normal music sounds are attenuated and garbled and not just the cracking noise.


If you have an external amp it is located on the floor under the middle of the passenger seat, the wiring to it is usually visible - there are 4 twisted pairs of wires (speaker wires) and a silver signal cable going to the amp.

There is no amplifier there. I looked up pictures of what it should look like.

[duanew]

No external amp on 650s, you can always install one but that does not to be your problem!

Yes. I might install one though if I figure it out.

[vtl]

Front driver side speaker died somewhat strangely in my 05 XC70. Sound was disappearing, sometimes with loud clicks. Fo some time I was able to bring it back to live with volume knob set to max and selecting a track with lots of low frequencies, but finally it passed out. I replaced it, and all is ok now. Bad speaker had broken/burnt wire coil, I saw it was changing resistance from normal to megaohms when pushing diffuser by hand.

So the new loudspeaker did the deal, the only thing I regret I put the same crappy 40W speaker and did not take a chance to upgrade them to 50W version, which sounds much better in our other Volvo. Multiply so-so speakers by so-so built-in amplifier in HU650, and the car's stereo sounds awful.