2007 LX Audio Issues - No solution? (2 Viewers)

[Preston Palmer]

2007 LX Audio Issue -

Very strange audio issue that no one has posted about, and I am out of ideas, and running out of hairs to pull out.

AUDIO - Works perfectly when I first start up in the morning.
PROBLEM - When I turn the car off, then back on, there is NO audio from anything. Even the little "beep" when pressing the nav buttons or temp up/down no longer works. I cannot get audio from any other source (aside from headphones plugged into the rear seat unit.) The audio works perfectly even on a 4hr drive through a whole tank of gas. Until I turn it off. Off for 10 seconds, or 3hrs. No audio on restart. Unless it sits for about 12hrs....... Then 9 in 10 times it works perfectly.

TROUBLESHOOTING
1. All fuses are good
2. Amplifier removed and sent to United Radio. Tech found no fault, and sent it back and said to send in head unit.
3. Head unit removed and sent to United Radio. Tech found no fault even after putting it in an oven.
4. Outside (or inside) air temp makes no difference. Radio works no matter how HOT or COLD it is inside so long as its been off for about 12hrs ish.
5. Disconnecting battery for 10 min then reconnecting does nothing.
6. Ground on amp is good
7. Voltage to amp tested good

Assumptions:

1. The ONLY thing I can think of right now is that the amp doesn't turn on when the battery voltage is high "ish" and it works fine after the voltage has dropped slightly from sitting overnight? I'm not sure how to even test this reliably except from take a voltage reading before I start the car and find out if there is a "cutoff" point. Even though I'm not sure that's the problem...
2. Some capacitor or something isn't discharging as quickly as it should?
3. Wiring harness? (Except I would expect a very different symptoms?)


UGH! If anyone has figured this out, or had similar issues, PLEASE let me know! I'm struggling to diagnose this one!

 

[jerryb]

you don't think they tested the amp at 14+vdc? I would think they would. idk. you think your voltage regulator is failing? Can you watch battery voltage on your phone before you shut it down, and then check it cold 8 hours later? I on;y ever notice about a 1 volt swing. 12.6-13.7(cold high idle)

if it was mine I would unplug everything not needed except enough to keep the screen alive and it's comms with the stereo. Leave amp plugs alone.

you can read the pdfs and figure it out. You;d need one or two on the screen, and two on the stereo. The rest you can unplug and see what changes related to the power issue. This would be my easiest option without thinking too hard and looking for results, eliminating most of the 10 connectors, or 11.

Seems like you have to go on the assumption that the amp and the stereo are good. If you get the same failure I'd think wiring in one of those connectors.
if you always have power on the battery and ACC wires, and some IG in the screen plug I'd think about the screen issues. If you loose power on the one of those I'd think car side harness.
Same with stereo plugs, but you'd have seen that already if it didn't light up, or the screen MFD lights up and not the stereo. Clean the 30amp amplifier fuse really well.
it's hard to be specific when you don't know what people have done, or in what order they did things or the exact conditions about the failure.

could also be one picky 10amp gauge fuse. I know it's horrible to say but if you haven't removed and cleaned or replaced every single fuse in the car that's 13 years old now, you should.

It's also hard to suspect wiring behind the screen unless someone else has been there working. if so that's number one suspect. Second stereo amp, third screen. Fourth stereo. (after all fuses, battery voltage, and alt.)

BODY ECU, ignition switch, umm, im rambling.

 

[nukegoat]

I don't trust that conclusion that the amp is good. You can verify that the "turn-on" signal from the radio is getting to the amp quite easily.

Often, when people have audio issues with these vehicles, it tends to be an amplifier problem (at least from my experience). It could be the amp turns on fine after sitting idle for a long time for some reason, which is why the amp people said it was fine upon initial testing? I don't know.

 

[ramangain]

I have a stock 01 ML amp collecting dust. It was fully functional when I removed it. If it is compatible with your system, pay for shipping and you can use it for testing.