Alright, so I'm putting a BOSS Audio Double DIN Head Unit in my 2001 Cadillac DeVille Sedan (Base model, not DHS or DTS). It does NOT have the Bose System, but it does have Onstar (which I think may be the source of the problem). I bought the OEM female harness adapter, and spliced it into the harness that had come with the Boss Head Unit.

Long story short, the Head Unit powers up and functions, but there'* no sound coming out. Through a bit of research, I came to the conclusion that I need a GMOS 06 harness to retain Onstar (not that a give two hoots about Onstar, but from what I understand, it needs to function or be bypassed somehow to power the speakers), but I'd really love to know some tips or ways to solve my problem without the GMOS 06 harness from experts/semi-experts/anyone-who-knows-more-than-I-do.

I thought I heard something about jumping a little pink wire in the OEM harness to make it work but I have no idea, honestly, and I'm not screwing with OEM stuff unless I'm 110% sure.

Any info is so incredibly appreciated, I want this thing in, working, and done with.

All the schematics I have (online, certain auto parts chain) show all Devilles having external amplifiers with any radio option code. I'm sceptical of this, but I don't see any that don't have the shielded /twisted pair wires from the head unit feeding an amp.
Did you see any twisted pairs of wires with foil sheathing on the harness from the head unit?

I looked through the car quite a bit but found no amp. I did find these transparent wires on the OEM harness, but no foil sheathed wires.

The more I look at that, I believe you do have low level outputs as evidenced by the pairs that have the electrical tape around them and the multiple shields covered in the clear plastic tubing. The colors are different between non-amp models and models with in amps if you have anything to reference.

My only experience with the DeVille is the amp that is buried (driver'* side) between the plastic cover (visible from the trunk) and the backseat.

Being a class 2 bus car, there is nothing to turn on an amp without an OEM stereo. I believe that is where the story of jumping the wire comes from. There is some truth to this with some systems of this era, but I don't have any first hand knowledge to impart, even though I love an electronic challenge.

Do you happen to have the small woofer in the center of the dash, as well as the big one in the middle of the rear deck?

If you go to the Crutchfield site and enter you car, you will see a lot of information and pictures. Even the very basic stereo they are showing has the external amp and 2 ohm speakers.

Yeah I do have a small speaker in my front dash and a 9 or 10" sub in the rear deck.

And ill go check out crutchfield now

Also, any info on installing the GMOS 06 or OS2 GM32 kits for supposedly fixing my issues would make a world of difference.

If I have to dump the cash on some kind of interface, so be it, I just want to know that it would work before I go buying stuff, you know? My dad got me this radio as a gift and I think he feels really bad that it isn't going well and I can't afford to have a professional do it, so I'm ready to do just about anything (short of re-wiring the speakers straight to the head because door panels and I do not get along)

It does look like the GMOS-06 is the one you would need. Appears to me that it changes everything to low level out puts and turns on the factory amp, besides retaining other features and the minimally valuable (IMHO) On-Star.

I thought sure there was a jumper harness to just by-pass the amp, but I can't find one. I suspect the sound would be poor if just using the door speakers anyway, in comparison to the factory setup.