This is a harness I was able to make to plug directly into the factory plug that goes to the Bose amp, to bypass and use my Alpine Amp instead.

Parts required:

Metra 70-2003 GM 1998-UP I used 2 of these harnesses, as if you want to use the Bose amp turn on for your amp you will be 1 wire short.

Several feet of the following: speaker wire, 14GA wire for amp turn on, either split loom or spiral loom to make it pretty :-)

4 RCA connectors (Radio Shack PN 2740319)

Here is the Metra Harness




You will need to use needle nose pliers to remove the 2 grey strips that retain the wires



Next use a small jewelers screwdriver and from the pin side insert it into the space and release the clip holding the pins. Rearrange the pins to the correct format for your factory setup. I have the pinouts I can send for the '06 Sedan, PM me and i'll send them to you.

Next I soldered the harness to speaker wire, and to the amp turn on lead. Then on the other end of the harness I soldered RCA plugs for the 4 channels coming from the head unit. I plan on getting some plugs for the speaker wire, but for now I just stripped the ends for a test fit in the car.

When finished wrap the wies in a loom for a clean look. And if you have a label machine use it to tag the wires and eliminate confusion.

Here is a couple of pictures of the completed harness.






Now I just have to build the amp rack in the car. I have all the materials, just need to find the time to build. And with it being over 100 several days this week the garage is not looking very inviting, so velcro is going to keep my amp in place for now.

Pete

 

well done! i love not having to hack into the factory wires... somebody should start mass producing a harness like this

 

2nd That

 

blacksheep where in NC are you? <-- raleigh

 

So all your speakers will run off of your aftermarket amp?

I thought the Bose HU will still be a problem with the aftermarket amp?

Sorry for the newb questions. I just want to understand it better before I do this.

 

bumpo

 

from what i have read...the bose hu puts out PREAMPed signal at around 2v or very close to it.

The bigger problem would be the factory bose speakers. Do consider replacing these if you are going to be bypassing and upgrading your amp. (I recommend Infinity Kappas)

This harness is kick a$$ and would definately recommend it for the simple fact that you do not have to cut factory wires (a major plus if you have a lease).

well those are my 2 cents

 

Yep N. Raleigh. PM me for me specific.

 

Got everything hooked up. Works pretty good with the exception of 2 issues:

Sometimes when i turn on the car it sounds like the speakers are only getting a few volts of power to them. I have checked the connections and they are good. It sounds muffled and very low volume, turn the volume way up, and something happens and the speakers sound normal, or if you cycle the ignition it will work fine. Is this caused because my Alpine amp does not support Differential speaker inports, so it is getting confused as to the actual sound level requested from the HU? Would a Differential LOC help?

I am going to install a LOC, the harness will still work as designed, but the RCA's are not needed.

2. got some weird shifting going on, may be because the amp power lead is too near to ECU, or may be my imagination, will see after i get the LOC. For now the external amp is disconnected.

Anyone have a reco on a LOC? I think i saw in a sticky sondgate makes a good one.

Anyone else having issues with this site? Seems the past couple of days DNS has been having issues and it gets to the front page, but thats as far as it will go.

Thanks,
Pete

 

Up to you if you want to cut/tap into factory wires. You can use a Scosche FD05B and FD05RB repin the harnesses, may need some extra pins, or 3rd harness to steal pins from.

Not really sure what you afre asking for. The harness I built allows me to use an aftermarket amp, using the factory wiring to/from the head unit, and out to the speakers.

Pete

 

No problem, just be sure to do some searching for an amp that takes differential inputs, my Alpine MVR-F345 seems to be acting funny, and I suspect it is the signal from the HU and my amp not being differential compatible, I am going to try a LOC next, and have been looking at getting an EQ to balance the flat output from the HU.

Pete

 

figured out i don't need an LOC. One of the connections going to the speakers was touching the case for the amp chassis grounding that connection and causing the amp to power down. As for th ECU I think that was because the battery had been disconnected.

Pete

 

i have searched, but only found people talking about USING an LOC, but what is it? im quite curious

thanks

 

an LOC is a Line Out Converter. (also called a hi/lo converter)

Basically from my understanding what its supposed to do is convert the high voltage? to low voltage? (2-4 volts)? and speaker level to rca.

correct me if im wrong people but im pretty sure of thats what it does

 

Yep you got it. A LOC converts High Lever speaker level outputs from the Headunit into low 2-5V RMS output RCA connections for hooking up an amplifier.

The harness I built here works fine for me now that i found and fixed my ground issue. No LOC needed since stock bose HU only puts out 2-2.5V RMS, which is just right for feeding my Alpine amp.

Pete