I have a '92 25th Z, 17k orig. miles...etc. I bought it last summer.

Has a Declo/Bose Gold Series Tape player and shows a manufacturing date of 6/2/92 so it should be the original radio.

My car has an 8 speaker set up. The usual 2 in the top dash, 2 in the B pillar. But also has 2 kick panel speakers and 2 rear deck lid speakers. These are stock, part of an option from factory. The rear lid even has a lock that works w/ my door key. I believe this is a very rare option.

Problem is this: Only the front 2 kick panel speakers work. The other 6 don't. I took the speakers out and wired them to another amp and they work, so then I took the radio out to see what was going on w/ the wiring. Strange thing is there are 5 male connectors, but the radio only has room for 4 male, multi-pin connections. Nothing looks like it was messed w/, looks all original.

The radio also only had 3 of them plugged in.
-1 black, 6 pin connected
-1 blue, 4 pin connected
-1 white, 4 pin connected
-1 blue, 4 pin Not connected
-1 white, 4 pin Not connected

The 4th connection on the radio fits nothing in the wiring harness. I swapped out the other blue and white and got nothing... so the only combination that has any speakers working is the current combination.

Any ideas??? I've had the car for a year and all else is working great. Just want 100% of this car to be original and functioning. Last thing on my list is this stereo (and buffing out some clear coat scratches...very minor).

 

Here is a pic of the optional/additional 4 speakers: kick panel speaker and the far rear speakers

 

From those pics, your car appears to be LIKE NEW. Love to see some pics of the whole car. You may have problems with your head unit, such as blown output transistors or something else that can cause an output failure. Does your system have a separate power amplifier besides the subwoofer amplifier, hidden somewhere in the car? If it does have an amp and the amp is bad that could explain why your speakers are not working. My 86 has a separate amp under the passenger kick panel, however it is not a Bose system like yours is. Have you tried to power the non-working speakers from the plugs that connect to the back of your head unit? That will rule out a wiring problem. M&R radio repair does good work on factory HU's. As for the rare option, it may be rare? I have not heard or seen one like yours before. Hopefully some of the more knowledgeable members here will chime in and answer that question.

 

That is pretty rare I believe. The wiring diagram only shows 4 amplified speakers, so it is possible that the other 4 are wired in parallel with the other 4. The extra white and blue connectore may be an un amplified speaker circuits as they do not have the shield.

Those CDM's (top half of radio) are pretty tough but I have seem a FEW with blown amps.
Try to find another CDM and swap it out but remove the amplified speaker fuse before powering it up. That will tell the story.
I do have a bose radio from a 92 Caddy that works if needed.

 

i had an iroc with the same speaker options, ive only ever seen 5 cars with that setup

 

Yes, my Z is like new. Trying my best to keep it that way! I don't have much paper work history on the car. Just the stories the previous owner told me and she couldn't tell me much. She didn't even know it had a spare tire...

I pulled off the rear trunk lid speakers last night and it appears the amp is attached to each speaker. 4 wires to the amp, then from the amp, 2 to the speaker. I'm going to pull one back out and and post some pics. Same w/ a front kick panel speaker (I haven't pulled that one to see if it has its own amp).

How do I check to see if the a head unit or separate amp is blown?

 

You can attach a speaker, one at a time to each of the 4 channels out of the back of the radio. Without amplification there will be sound just not as loud

 

perhaps a search can yield some results, it reminds me of the bose option stuff the berlinettas had, i wonder if it was a continued option in later years, in any case beautiful rare car, love it

 

I have an 89 iroc with the bose option. There are 4 speakers in the system. One in each kick panel and the two in the rear deck panel. The bose system has a little silver amp for each speaker at the speaker. These are notorius for going bad. It is a well designed system and I ended up taking the bose speakers out and replacing them with infinity kappas and a kenwood deck and amp. I also added the sail panel speakers and the plate speakers in the dash and it sounds better than any camaro I have ever heard. I have a 92 Z vert that I have added the kick panel bose boxes to loaded with infinity kappas. I used a 5.5 inch speaker in the kick panels and used silicone to seal them so the box would develope all the bass it is designed to make. If you decide to do as I have done be sure to keep all the factory wiring and parts since it is rare so you can return it to stock one day. Would like to see some pictures of your car since I havee never seen a red bose system before. Mine is black and I have seen gray and tan but never red.

 

I have an 89 with the same option. Which I agree is very rare.
With mine only the two rear speakers are working.
I plan to start tracing power etc over the Thanksgiving holiday. If I run into a good solution I will be sure to post!!

 

I have the same speaker setup in my 88 Iroc-Z. Was looking into to restoring it or going w/o it. Previous owner(s) cut out the radio harness as well.