I've been doing a lot of research on this.
If I understand you correctly, I can use the CD aux input on my deck to add the aux line in.

Part#16151312 - Pontiac Delco cassette with 7 band EQ (95-2000) installed in a 88 GTA

I just need the wiring diagram for the harness more in the middle of the deck (9 pin) Then I could wire directly to that and would use the stock "tape/play" button to switch from tape to CD (in this case to play my mp3)

All I need to do is wire the "T-on" and the left and right line in and negative, correct?

Wondering if any has the wiring diagram for the optional CD player ? I have the 20 pin diagram but not the optional CD player harness.

This is like my deck with stand alone CD player ( I don't have the CD or Aux in like this one. I want to use the optional CD port as my aux in....that way all I have to do is press the "Tape/Play" to listen to the CD line in - the deck will think its the CD player....
This way I don't even have to open the radio, (I believe)






I need help with the unknowns #8 & #13 - figure the CD must send a signal to the deck to stop the radio/tape signal and accept line in.

7-Pink-Radio Sig (on)
8-Grey-DIM DIAPLAY (Beats me what that means)
9-Blank10-Light Green-Right Aux in
11-Orange/Black--Left aux in
12-Light Blue-Audio common
13-Black/White-GND14-Dark Green-E+C BUSS (again, no clue)
15-Orange-Battery


Thanks Any help is appreciated.

 

You might want to check out the products by Prcision Interface Electronics for what you want to do. I did similar with a 2002 CD deck from a Chevy/GMC truck in this thread...

https://www.thirdgen.org/forums/car-...elco-head.html

The GM9-AUX that I used makes the radio think it has a CD changer hooked up to it and plays the SIRIUS audio through the auxiliary harness. This one may not work for your radio, but they have others that should.

http://pie.net/

 

Thanks, I seen one I think would work, but it's over $60 dollars. I have seen others do this mod (not to the opt CD output) for $0.00 dollars! Using an old head phone jack!

I believe this can be done without opening the radio. Just have to figure out the 9 pin wiring harness - it uses PCE protocol (this tells the Head unit whether to take signal from the Tape or opt. CD.
Just need a better understanding of a few pins.