The Day the Music Died

You did hang up the phone, didn't you?

 

So it's Bye Bye Miss American Pie?

 

XM went out of business while you were taking that call. :madgrin:

 

Are you sure the other person's phone disconnected?

 

Hi Evan,

I assume you have an aftermarket config since you mention XM and Bluetooth on a 2004...

When making a phone call, are you using a hands-free mode where the sound comes through the speakers? If yes, then you can rule out a blown fuse since you can select various stations via the MFD (which proves the radio receiver assy has power) and the speakers work (which proves the JBL amp has power.)

The JBL amp has a mute circuit where the radio receiver sends a voltage to mute the amp when switching between various audio sources. When the amp is supposed to be working, the voltage on this circuit is >3.5V while the voltage is <1V when the amp is supposed to be muted.

Maybe this circuit is not working when the XM tuner is on and the mute voltage remains below <1V, thus keeping the amp silent. Or, maybe there's a problem with the XM tuner not providing an audio signal.

If you have a digital multimeter and feel like checking voltage on the mute circuit, see attached file.

 

Hi Evan,

See my prior msg and attached file.

 

Have you had your ears checked?

Tom

 

Since Evan can make phone calls I have to assume his ears are OK.

 

Hi Evan,

Actually, it would be easier to find the mute terminal at the JBL amp wiring harness connector (S15-1), under the front passenger seat. You can measure voltages there. If necessary, use a small pin to gently puncture the wire insulation so that you can measure the voltage between the appropriate wire and body ground.

If you find that the mute voltage is at >3.5V as it should be, then I suggest you disconnect your aftermarket addons (XM, Bluetooth) to make sure they are not the cause of the problem - before you take your car in for service. With an electrical problem of this sort, the tech may refuse to work on your car given the presence of the aftermarket accessories.

 

You could try that for fun, it won't hurt. Or else find and remove the fuses that provide power to the audio system: ACC, DOME, and AMP.

 

You know... I think this may be the first time I've seen Evan asking a question.... He's one of the folks who supplies the answers around here!

 

Hi Evan,

1. Yes, you have to remove the clips in order to get the cover off. I haven't had need to do this on my car. Don't be surprised if the clips break while you are trying to remove them.

2. You need to leave the wiring harness connector in place. If bare metal at the wiring harness connector is available for you to probe, no problem. Otherwise you need to use a small pin as I suggested in a prior post.

3. Ignore the other parts of the procedure. You're just trying to see if the MUTE voltage is above 3.5V when the radio is on, without having to disconnect wiring at the radio control head, etc. If the voltage is correct, then check your aftermarket setup to make sure that's not causing a problem.

If the voltage is low, then either your radio control head or the amp has a problem, so let your extended warranty take care of that.