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Discussion Starter #1
Hi everyone,

My wife's 2007 Sequoia has an electrical issue that I'm having a difficult time diagnosing...

1) The stereo is the factory JBL stereo, with the mid-woofer/tweeter speakers and the external, factory JBL amp that is located just underneath the center console.
2) When the volume on the head unit is turned up past "34", the sound coming from all speakers starts to distort. It does this regardless of the source of the material - CD, radio etc... it does not matter. Same problem exists.
3) I replaced the head unit with an aftermarket unit (and connectors) from Crutchfield. That did not resolve the issue.
4) I replaced the front speakers with new, suitable replacements (also JBL). That did not resolve the issue.
5) I replaced the factory amp with another factory amp. That did not resolve the issue.
6) I checked the stereo ground, and that was consistent with the other wiring coming to/from the head unit.

Can anyone think of what else I'm missing or what I can try?

Has anyone had this issue and successfully resolved it?

If so, how?

I've thought about putting in a new head unit and hard-wiring everything - power lead from the battery, fuse in-line, new speaker wire run to each speaker etc... but firstly, that's a lot of work and secondly, the factory speakers are an odd ohm rating and while I doubt the load rating would likely be a big issue for an aftermarket head unit, I don't want to have to replace every speaker in every door...

Also, I'm not sure if hard-wiring everything with the new head unit would cause any issues with the factory wiring system - ie: I have a Jeep that uses that CANBUS system and if a stereo is not detected, the vehicle may not start (I believe it's a theft-deterrent built into the code that CANBUS runs on). Do these Sequoia's have that issue?

Any advise is appreciated as I'm just really curious about what is causing the issue and would like to resolve it as soon as possible.

Thanks!
 

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boulderskies
2006 Tacoma
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144 Posts
boy that's a head-scratcher. 2 things come to mind:
1. is there a way to run a ground wire to by-pass the existing? just a wire straight to a good ground.
2. run a wire from the hot to the battery. again, just a wire run outside to the battery.
google your "yr/make/model wiring diagram" and you'll find images that will be very helpful.

scott
 

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2,604 Posts
Well, having the same radio, in a different vehicle, that I have never worked on, makes me imminently qualified to offer my opinion. You've been warned, take it for what its worth.

The whole system is odd on my 2006. The factory wiring from the HU to the amp is not the normal 2 wires per speaker, plus extra for subwoofer, it is some kind of bus communication across a Tx+ & Tx- wires, so another place to look for weird stuff happening. Should be a Red / white and an Orange wire for those two. (in 2005, you colors may vary) The iwres to the speakers then run from the amp to the speakers. Not sure if this is plain wire, or shielded twisted pair. So if and when you rewire, you have more work to do because of this setup.

Also, just a thought, do you have a cell phone charger, or other after market electronics in the vehicle. Remove / unplug any of those, see if your problems go away. I've seen several instances on other forums of cheap cell phone charges putting interference into radios. Would not surprise me if cheap radar detectors, dash cams, hair dryers, you name it, also caused problems. I had a problem with a Verizon supplied charger a few years back that gave weird noise in one vehicle, but not the other, after about 1 year of use.
 

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boulderskies
2006 Tacoma
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144 Posts
i just thought of something else: Crutchfield's website has a kick-ass car stereo section. you can look up year, make and model of any vehicle and get a TON of documentation and diagrams on the stereo set up including wiring diagrams. it might be useful to research your vehicle there for wiring info.
 
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