White noise from speaker (1 Viewer)

[kgrove]

I'm stumped on this one... I'm getting a static / white noise sound coming from my driver's side speaker. What makes it confusing is the noise is there even when the stereo is powered off. Other information that might help in diagnostics: 2007 LC with Nav - no modifications to stereo. Over the last year or so, the front speakers started working only intermittently and recently basically not at all. I'm looking at three possibilities:

One, the factory amp or head unit is bad. Normally I'd go right to this diagnosis but it seems odd the noise is present even with the stereo is off.

Two, the speaker or amp for the hands free phone is shorted out or just playing static all the time (I assume the hands free phone uses a different speaker, though I guess it could just be running through the front left stereo speaker).

Three, the "announcement speaker" (the machine that goes "ding" when I leave my lights on or forget a seatbelt) has a problem.

Given the front stereo speakers have been malfunctioning the last year, I suspect it is #1, but it is possible that there are multiple problems and the white noise is unrelated to the front speakers not working for music.

So... What's the easiest and least intrusive way to figure out the cause of the noise? Ideally there's a logic flow of just turning some things off and on or running a couple simple tests that can confirm where the problem is before I start pulling door and dash panels or removing the passenger seat to access the amps. If not, where would you start and how would you test it? I probably need to access the amp anyway to figure out why stereo only plays through the rear speakers...

 

[Ninja Cruiser100]

I have a 2007 gx with exactly this issue in the shop for inspection. I’ll report back on the diagnosis once I get it. FWIW the Lexus Dealer could not figure it out.

 

[Njck22]

Noise still comes out with the stereo powered off? like the volume button pushed in to turn audio off and white noise still comes out? Certain channels going out can be related to amplifier failure. And you are also certain the speakers are not blown?

Could also be the navigation ECU, it takes the speaker wires from the amplifier for the driver side speaker only, and then sends its own signal for voice navigation. Unfortunately for diagnosis, no way to only remove the navigation ECU and still have regular audio going to the drivers' door. I would pull the amplifier (not very difficult) and then see if you still get static, that would without a doubt confirm the navigation ECU as the culprit.

 

[kgrove]

Noise still comes out with the stereo powered off? like the volume button pushed in to turn audio off and white noise still comes out? Certain channels going out can be related to amplifier failure. And you are also certain the speakers are not blown?

Could also be the navigation ECU, it takes the speaker wires from the amplifier for the driver side speaker only, and then sends its own signal for voice navigation. Unfortunately for diagnosis, no way to only remove the navigation ECU and still have regular audio going to the drivers' door. I would pull the amplifier (not very difficult) and then see if you still get static, that would without a doubt confirm the navigation ECU as the culprit.

Yes, there is noise even after I power off the stereo (I.e., push volume button to shut off head unit and antenna retracts). I suppose I can try plugging a destination into the nav and see if the nav system audio is working at all... its been years since I used the nav. How does that work for sound? The speakers can only have one input, so I assumed the nav system fed a signal to the amplifier for just that channel? Is there a separate speaker for the hands free device? Or does it also feed through the amp and to the front speaker? I know the hands free works even though the front speakers dont make sound for anythig else... well, anything else but white noise. BTW - where is the brains for the hands free system? Is it in the head unit, the nav system, or is it its own thing?

Anyone have a wiring diagram for the head unit / amp / nav / hands free for a 2007 LC with nav?

 

[Njck22]

 

[Njck22]

The third image shows what you want. basically, the amp sends the pink and purple pos and neg speaker leads to the navigation ECU, which then will shut off the music pass-thru and send navigation instructions through that. Does hands-free cut off only the drivers speaker? I believe it is run through the multi-display, which send the signal to the radio and player. or it sends through the navigation ECU, if it only comes out the driver's speaker.