GX470 no volume control

[Nothinghead]

A strange problem started today in my 2005 GX470 with standard audio (no nav, no ML). There is no volume control, no sound from speakers. All functions seem to work just fine from tuning, changing source, etc. There is no sound and when I turn the volume knob or push the volume buttons on the steering wheel, there is no response, no change in the display (normally shows the volume setting momentarily). I checked the ACC fuse and both Radio fuses and they are all good. The only modification I have done was add a GROM bluetooth unit a few years ago. It's been in the 70's here in Boise, no water crossings, no rain leaking into the car and it worked this morning.

Does anyone have an idea what might be going on?

I may need to just replace the head unit with OEM but I'm unsure if there is an amplifier outside of the HU that could be the problem and would continue to be the problem after plugging in another HU. I'd hate to have to run new speaker wires throughout.

 

[Onefastrx7turbo]

I have a non NAV head unit

 

[Nothinghead]

I have a non NAV head unit

Same here.

 

[Onefastrx7turbo]

I mean I have one I'm no longer using.

 

[Nothinghead]

I mean I have one I'm no longer using.

Even better. I'm sorry I misread you. Would you be willing to part with it? PM me a price shipped to 83714 if so.

 

[langsen]

Check the amplifier under the driver's seat. I also have non-nav non-ml, and mine was acting like this when the amp was damaged. I replaced the reverse voltage protection diode in the amp, about $4 locally, and it worked fine again. No idea why yours would have been working fine earlier in the day, maybe one of the wiring connectors under the seat got loose somehow.

 

[Nothinghead]

Check the amplifier under the driver's seat. I also have non-nav non-ml, and mine was acting like this when the amp was damaged. I replaced the reverse voltage protection diode in the amp, about $4 locally, and it worked fine again. No idea why yours would have been working fine earlier in the day, maybe one of the wiring connectors under the seat got loose somehow.

Looking more into this, I agree, it seems like it is the amp. I've unplugged it and plugged it back in again and no change. When I get home, I'll check the continuity to the amp as per the TSB I found on ClubLexus.com.

How did you know to replace that diode? My electrical engineering knowledge isn't the greatest.

 

[Nothinghead]

In testing my amp for continuity (as per step 6 in the tsb above) I decided to check radio fuse no. 2 again and, though it looked good, I swapped it out. Now everything works as it should.

Damn fuses.

 

[kolbydmc]

Not to beat a dead horse but, did this solution continue to work? I have the EXACT same problem and I was beginning to think I should blame it on the GROM. I too checked the fuses and they were fine, thinking about replacing fuse no. 2 and see what happens.

 

[Gunsup007]

I know this post was several years ago, but I'm having the same issues and thru research came across this post. So, after trouble shooting my own issues, I know it is my amp. Anyone on here still have a good working original amp they want to sell me? I have a 2004 Non-Nav. non ML system. Just the basic system but need an amp.

 

[Nothinghead]

This happened to me again a few months back and I unplugged the large dash wire harness just left of the hvac controls (the big one secured with a 10mm bolt) and plugged it back in and everything has worked since.

I did just install an aftermarket head unit yesterday and with the wiring harness adapter, lost sound to the rear speakers. I may be adding and aftermarket amp so I’ll let you know if my OEM amp becomes available (but you probably don’t want to wait a few weeks).

 

[Gunsup007]

This happened to me again a few months back and I unplugged the large dash wire harness just left of the hvac controls (the big one secured with a 10mm bolt) and plugged it back in and everything has worked since.

I did just install an aftermarket head unit yesterday and with the wiring harness adapter, lost sound to the rear speakers. I may be adding and aftermarket amp so I’ll let you know if my OEM amp becomes available (but you probably don’t want to wait a few weeks).

Thanks for the reply and update. When you say big wiring harness, I know if the ones to the left of the driver in the footwell and the one to the right of the passenger footwell. Are those the ones your talking about or is there another one I'm missing?
Also, keep me updated on your amp. I'm interested.

 

[Nothinghead]

Thanks for the reply and update. When you say big wiring harness, I know if the ones to the left of the driver in the footwell and the one to the right of the passenger footwell. Are those the ones your talking about or is there another one I'm missing?
Also, keep me updated on your amp. I'm interested.

I mean in the center stack. If you pull the wood trim that holds the hazard switch (gotta pull off the gray trim left of the shift lever first), there is a big wire plug held in with a 10 mm bolt. It’s how all the stereo stuff plugs into the car.

 

[Gunsup007]

I mean in the center stack. If you pull the wood trim that holds the hazard switch (gotta pull off the gray trim left of the shift lever first), there is a big wire plug held in with a 10 mm bolt. It’s how all the stereo stuff plugs into the car.

View attachment 2009256

Oh got ya. Thank you so much, I'll check that this evening.

 

[Gunsup007]

Well I gave that a shot and still no sound. It's definitely my amp. Let me know if you would like me to buy your old one.

 

[Nothinghead]

Well I gave that a shot and still no sound. It's definitely my amp. Let me know if you would like me to buy your old one.

I don’t think my wife will let me get new amps any time soon.