New head unit/Bose system problems

I've got a 2003 Yukon with the factory Bose package. I've done a lot of seraching, but haven't quite found the answer I'm looking for. The previous owner of my truck had a Sony XNV-660BT head unit installed. From what I remember him telling me, when the new unit was installed, it didn't work correctly with the Bose amp, and was either too loud or quiet. He took it back to the shop, and apparently just had the amp bypassed and now the speakers connect directly to the back of the head unit. Now, the system works, except the front and rear small pillar have no functionality, only the 4 door speakers and sub work.

I was wondering, was the guy who worked on it retarded, or are there actually problems connecting an aftermarket head unit to the Bose amp? Is an adapter or special harness required? I just want to make sure I'm getting all I can out of the speakers I have. Thanks for any help.

seven9st surfer said:

I was wondering, was the guy who worked on it retarded, or are there actually problems connecting an aftermarket head unit to the Bose amp? Is an adapter or special harness required? I just want to make sure I'm getting all I can out of the speakers I have. Thanks for any help.

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There are certain/correct adapters you need. But there's no reason for him him not to use it and it work correctly. He probably just took the cheapest way out because the correct adapter is around $80

The problem you might have is if he cut the harness up and threw the connector away.

Are you able to take your radio out yourself? Where in Jax are you? If you're not too far from me, I could look at it. I worked off and on at stereo shops for over 15 years...

I'm acutally on deployment right now. I just dealt with it for a while, but it started bugging me before I left. Now I'm just trying to do all the research so I might have an answer when I get home. But yeah, I'm planning on pulling it out and doing the work myself. You know what kind of adapter in particular I'd need? The only ones I've come across that specifically say they work the Bose system are the On-Star adapters. I don't use on-Star, but if it'll get all my speakers working, I'll take it. Thanks for the help.

http://www.sonicelectronix.com/item_12901_Axxess-GMOS-04.html?gclid=CIOwxMzX_LECFdNxMgod_X4AdA

you would need one of these, thats assuming the guy before didnt just cut out the harness and screw up all the stock wiring

alc5m said:

http://www.sonicelectronix.com/item_12901_Axxess-GMOS-04.html?gclid=CIOwxMzX_LECFdNxMgod_X4AdA

you would need one of these, thats assuming the guy before didnt just cut out the harness and screw up all the stock wiring

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Yeah, that's one of the ones I was looking at. They place all the emphasis on the On-Star capability, I wasn't sure if that was what I needed. But it sounds like it is! Thanks! And if the wires are cut, I could get something like THIS and just replace OEM harness, right?

Gonna go ahead and necro-bump this, cause I got some more info. Turns out all 8 speakers are working correctly, It's just that the Bose amp was bypassed. Apparently, when the HU was installed, the lowest volume was still incredibly loud. He said the guy installing it said that the internal amp of the HU plus the Bose amp was the cause, hence the bypassing of the Bose amp, and only using the HU's internal amp.

Does that sound like a realistic problem, or was the guy talking nonsense? I really don't want to buy the adapter (looking at the PAC OS-2C-BOSE) and re-do the install only to find out that's what the guy had already tried. But I also want to try to get that amp working if I can. Anyone have any issues like this?

It sounds like when it was originally installed an adapter that uses high level (speaker) inputs was used while Bose requires low level (RCA) inputs. Hopefully the installer knew of the harness behind the a/c controls that you can use to bypass Bose, otherwise you could have a serious mess on your hands.

magicbus said:

It sounds like when it was originally installed an adapter that uses high level (speaker) inputs was used while Bose requires low level (RCA) inputs. Hopefully the installer knew of the harness behind the a/c controls that you can use to bypass Bose, otherwise you could have a serious mess on your hands.

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Yep what he said. It was "double amplified" so they bypassed the amp. The correct harness with low level would have fixed that.

mazdawg(Mikey) said:

Yep what he said. It was "double amplified" so they bypassed the amp. The correct harness with low level would have fixed that.

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when you say "correct harness with low level" what exactly do you mean? low level as in just play everything at a low volume, or would the correct harness automatically output a lower level or what? probably a stupid question, but i suck at audio installations

It's not a stupid question. I will try to be as simple as possible. The RCA pre outs on an aftermarket deck are what is called a low level output, basically there is lower "resolution" or a smaller "area for distortion". The wires from the internal amplifier in a radio that lead out to the speakers are a high level output.
Basically by wiring high level signal to an amp that needs low level signal, you give the amp twice the input it needs so it amplifies that and causes distortion and too much volume.
When we say harness with low level we mean a harness that has RCA jacks to plug into the RCA preouts on the aftermarket radio.