If you want to add an aftermarket cd player to your car that has bose, onstar, or even both here is the deal.

A few terms to know before starting:
Rap- the system that keeps your radio on until you open the door, or 10 minutes gone by after turning car off

Chimes- should be self explanatory, but this is what dings when you open door with key in ignition, turn off car with headlights still on and door open, and warning messages on dic's, etc. etc....

97-03 model years
1) The first way discovered and "hardest way". It is a harness that has 17 foot of about 18 wires that just relocates the factory radio to the trunk. Then you add your aftermarket cd player up front in stock location and it retains your bose because it is just a factory amplifier "bypass" *chimes will be retained and rap also* there are 2 harness part numbers:

a) 70-2009
b) 70-2054
price around $70

97-03 model years
2) The second way is the "20 dollar harness" and it is just the one 21 pin plug. If you just hook this up to the factory plug, no audio will go through the existing bose speakers. This is because you need to run a jumper from 1 of 2 wires *you can use the accesory wire (red) or the remote turn on wire (solid blue)* to the pink wire on the small black factory plug beside the antenna plug. This will tell the bose amp to turn on.
*will not retain onstar/chimes/rap* I have only seen one case where this did not work.

Part #70-1858
price around $20 plus 5" piece of wire

00-03 & 04-08 model years
3) the third way is to use the special harness that retains everything, bose/onstar/rap/chimes. It is just a plug and play harness, that is self explanotory, splice the plug in.

part # gmos-04
price around $150

dash kit part #99-3320

04+
These use a digital turn on for bose, so they are easier to retain the bose than the 97-03's

1) The first way is to use the "20 dollar harness" again but there are two of them, you can use. 1 you have to tap into the accesory wire yourself (I just tie into the brown wire on the ignition harness behind the tumbler), the 2nd is one with the accesory already and is like 25 dollars but is hard to find in stock anywhere. You lose onstar but retain bose/monsoon, also non-bose/monsoon can use this harness also; both lose rap, onstar, chimes.

a)part# 70-2003 (have to find accessory) price around $20
b)part# xsvi-2003 ( has accessory built in) price around $25

2) The second way is the easiest way to retain onstar/bose/monsoon/rap/chimes. It is straight forward, splice, plug and play.

Part # GMOS-04
price around $150

3) The other 2 ways use harnesses that retain the chime/accessory/rap but for non-amplified factory systems. plug and play hook-up. one harness is for factory navigation cars. Other harness is for non-bose/monsoon/non-onstar base cars that want to retain rap/accessory/chimes.

a)part # gmos-01 (works w/ or w/o onstar, provides wire connections to utilize factory navigation hookups) price around $130
b)part # gmrc-01 (works for base cars wanting to retain rap/accessory/chimes)
price around $75

DIN Dash kit w/ pocket part #99-3527
DOUBLE-DIN Dash kit part #95-3527

On 97-08 models if you are adding aftermarket speakers and not using bose/monsoon amp; you need to run speaker wires to stock locations because stock speaker wires are running through the amp tht isn't working.

Part numbers are from metra, since that is what I use everyday and doing this by memory.

-Steven-

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