No sound at all from any speaker

[Gerbil21]

My brother just got a 05 trailblazer Lt with an aftermarket Kenwood hu
According to to RPO code he had a 6-CD radio non-bose w/OnStar

So now to the problem.
There are no chimes and no sound when playing the radio, also the radio will stay on all the time if we don't turn it off.

They connected the radio with a harness like the gmos-01, there are some wires that aren't connected like mute but idk if that would actually mute it also there is a chassis ground. Also the can bus harness connector is there but only has two wires that are cut coming from it

Now what are his options?
He would like to just go back to stock but what is the year to year compatibility between the radios also can a non CD or single disc radio work? And what's the deal with locked radios.

If he stays with the hu what should we check to see if it works since there is no sound at all.

 

[Gerbil21]

OK I just pulled the dash I'm going to check the wires

 

[Gerbil21]

OK well from the radio side p.cont, ant cont, and mute are not connected

From the car side
Amp turn on
Dimmer
Phone
Illumination
And chassis ground are not connected

But at the pin where the disconnected chassis ground is there is another chassis ground wire that is connected to the radio harness

 

[Gerbil21]

OK so I checked speaker output wires and got .01v so maybe the hu is dead? Also it's a Kenwood kdc-138

 

[Gerbil21]

OK so apparently it came with Bose

so apparently they tried to add bose or something because on this thread
http://gmtnation.com/forums/topic/11044-convert-a-bose-non-lux-nav-h-unit-into-a-bose-lux-nav-h-unit/

i got this

15800000 WITHOUT Y91 or Y92 Option. (Bose Luxury Option)
15800001 For vehicle with Y91 or Y92 Option. (Bose Luxury Option)

UQA is the Bose speaker code for all year GMT360's and has nothing to do with either Lux or non-Lux amps

there is no uqa rpo code on the sticker so that means they tried to add it in. idk how far they went but it clearly didnt work or maybe it did but the hu died so should i get a oe hu or another aftermarket? or could it be the speakers that died due to no amp and incorrect parts?

 

[Sir ffeJ]

IMO

If you don't have the wiring diagram for the harness that's already in there, I'd pull it out and throw it away and start fresh with a new one. Who knows what they've done to it.
1) The harness could be dead
2) They hooked it up wrong and fried something(s)
3) It's the wrong harness to begin with

See if there is an amp in the rear passenger side quarter panel above the wheel well. If there is, it's Bose. Are there dash speakers? That's another way to tell, but the amp is a for sure.

 

[Gerbil21]

IMO

If you don't have the wiring diagram for the harness that's already in there, I'd pull it out and throw it away and start fresh with a new one. Who knows what they've done to it.
1) The harness could be dead
2) They hooked it up wrong and fried something(s)
3) It's the wrong harness to begin with

See if there is an amp in the rear passenger side quarter panel above the wheel well. If there is, it's Bose. Are there dash speakers? That's another way to tell, but the amp is a for sure.

yes there are dash speakers. so maybe someone swapped all the bose parts in? it dosent make sense to do that when you could just use better aftermarket speakers but idk.

also the on harness all the wires are labeled (description written on the wires) also i checked continuity of all wires and it came out good so idk how the harness can be dead? and the fuse on the radio and the one in the rear fuse block are good.

how can it be the wrong harness? all wires connect except for the ones posted above

 

[Blckshdw]

The part about the radio staying on when it shouldn't be, screams bad harness. My first GMOS did that, although I still got sound when I was supposed to. The Kenwood has RCA inputs on it correct? Hook it up to a stereo receiver and see if it sends a signal that way. If he's got a Bose system stock, the right harness should take RCA inputs and send low level signals to the Bose amp.

 

[Gerbil21]

The part about the radio staying on when it shouldn't be, screams bad harness. My first GMOS did that, although I still got sound when I was supposed to. The Kenwood has RCA inputs on it correct? Hook it up to a stereo receiver and see if it sends a signal that way. If he's got a Bose system stock, the right harness should take RCA inputs and send low level signals to the Bose amp.

i still dont understand how a harness can go bad can it really be made so cheaply that the contacts are free to move and end up not working?

also there are no connections coming out from the harness to a keyed power so maybe thats why it stays on?

there are rca connections on the back for a sub also acording to the rpo codes he got a multi disc radio but no bose.

 

[Blckshdw]

I went through 2 GMOS units that both failed, before switching brands and going with PAC. My first GMOS had the power issue like this one. It doesn't have ignition power, it is supposed to read the Class 2 Data bus, and THAT tells it when it's supposed to turn on, when it's operating under RAP, and when to turn off. If whatever circuit that controls that kicks the bucket, this is a problem you might get.

 

[Gerbil21]

Doesn't that only work when you have those boxes to connect to?

Also would Bose speakers even work on a stock hu? I was thinking of taking out a speaker from my 05 envoy w/Bose and plugging it in and seeing if it works even thought I'm leaning towards a dead hu since voltage on radio harness side was .01v with volume at max

 

[Gerbil21]

ok so we pulled the rear panel and he has a amp soo... idk why its not on the rpo code

 

[Blckshdw]

Any details on the amp? Picture maybe?

 

[Gerbil21]

it was definitely factory installed and now i remember a important part is that it had 3 rpo codes that said dealer option or option code im guessing the po got the bose installed after the car was ordered in the dealership

i will upload a pic in a min or so

 

[Gerbil21]

here they are

product#
15135032

 

[Sir ffeJ]

Now you need to know if the harness that's in there, is for a Bose system. there are different types of harness's for the different types of stereo equipment that our trucks have.

Different types
- non Bose / non on-star / non rear seat Ent.
- with Bose
- with On-Star
- with Bose & On-Star
- with Bose & On-Star & Rear seat entertainment
- with Bose & Rear seat entertainment
- with On-Star & Rear seat entertainment

I think that's all of them.

 

[Gerbil21]

Idk which the p.o had originally but I know he has OnStar and Bose one thing I noticed is that on the radio wiring diagram it shows the p. Cont. Wire as being able to turn on a amp but that wire is not connected and idk where it would connect to either Im going to see if I can find some wiring diagrams.

Also would not having the amp on cause the radio to not sent out a signal? Since I was getting .01v at the radio for the speaker output?

 

[ddgm]

Go to the www.crutchfield.com site and put in the vehicle with the options and the Kenwood HU and it will tell you what you need for a harness.

 

[Blckshdw]

Idk which the p.o had originally but I know he has OnStar and Bose one thing I noticed is that on the radio wiring diagram it shows the p. Cont. Wire as being able to turn on a amp but that wire is not connected and idk where it would connect to either Im going to see if I can find some wiring diagrams.

Also would not having the amp on cause the radio to not sent out a signal? Since I was getting .01v at the radio for the speaker output?

To rule out the module, go to Best Buy, get the Metra Axxess adapter for Bose and Onstar. Wire that up and see what you get. If it works, then you're good, if not, you can return it, and then try to figure out a way to troubleshoot the head unit. Being as the radio stays on constantly, I still say that module adapter is bad and has to go. The amp receives a turn on signal over the Class II bus, via the radio, through that module. I don't know how the module interprets that, whether it be from direct power, or audio signal.

 

[Gerbil21]

The only thing is that currently there is no module it is wired directly from the harness that plugs to the car wiring to the harness from the radio

 

[IllogicTC]

The only thing is that currently there is no module it is wired directly from the harness that plugs to the car wiring to the harness from the radio

And that could be the problem right there.

The Bose wiring is an interesting cookie. One interesting thing is that although the factory radio has 4-channel output, only the front 2 channels are fed to the amp, with the rear 2 being used to run the RSA feature.

Also, the Bose amp waits for a signal via Class 2 from the factory H.U. that it needs to turn on. Then it will begin accepting input and providing output. Until this signal is seen on the Class 2 bus, it'll remain off. Perhaps without the adapter module, it's not receiving this signal.

As a final note, I've read that generally swapping stuff out while retaining the Bose amp runs the risk of degrading audio quality. Some of this may be truth, some based on speculation on "mixing brands," and a final bit just based of personal bias (for example, people who want tons of bass are biased to get that, people who are more sensitive to mids will notice if they change, etc.). I cannot speculate on whether the aftermarket H.U. you have will provide superior, on-par, or inferior sound quality through the Bose system, it's entirely subjective.

If I remember correctly, the bass and treble controls are run through the amp also, and the fade definitely is (balance may be run via H.U. as it simply dims one of the channels or the other feeding to the amp). Pretty much when you adjust those controls, the radio tells the amp what the new settings are, and it applies them. This may be where people are figuring the apparent degradation in sound quality, if the Bose amp isn't allowed to flex its muscles properly there's no real point to having the name brand in there to begin with, some might say.

 

[Gerbil21]

Thanks for the I info my brother just bought a PAC OS-2c-bose harness so let's see how it goes if anything he can always upgrade the hu now with the correct harness.

One other question is what are good replacement speakers when staying with the Bose system?
I need to replace the dash speakers are there any good upgrades With all stock Bose system and how about for the doors?

Also what can be done with a stock Bose amp and good hu?

 

[IllogicTC]

The harness should get the amp to wake up and get tunes going.

I'm not sure on replacement speakers. The problem is the speakers are always weird impedances. For this system, the dash is 4 ohms, the rears are 2 ohms, and the fronts are 1 ohm. Just think, there have been instances in other vehicles where they've used a 0.5-ohm speaker!

 

[Gerbil21]

??? I'm lost when it comes to speaker specs I should go research about this more.

So I'm guessing most aftermarket speakers don't have that low of a resistance, so it's either stay with Bose or replace the whole thing?

 

[IllogicTC]

??? I'm lost when it comes to speaker specs I should go research about this more.

So I'm guessing most aftermarket speakers don't have that low of a resistance, so it's either stay with Bose or replace the whole thing?

That's the general recommendation, however I couldn't honestly comment one way or the other. Like I said, audio is very subjective and differs between listeners (audiophiles can never agree with each other, as proof) and I'm going based purely on what's on the numbers but paper and practice are two different things sometimes.

 

[Gerbil21]

ok sorry for the delay on the update but the harness came in yesterday and then last night we twisted all the wires together and it all worked great. the hu worked perfect chimes and onstar also works perfect and the sound is great

also just for anyone else if you have the same setup and your radio has a p.cont. wire (used for amp turn on) like my brothers then connect the blue/white wire from the pac harness to it and enjoy the sound

the only two wires we didn't use was the orange and blue from the pac harness.

And for everyone else- Thanks for all the help!

 

[Sir ffeJ]

glad it worked out for you