My wife says I don't hunt or fish or have any hobbies, but I do. I have a C4 to work on, it takes all my free time.
So here we go with the old Bose radio problems again. Anyone know radios? I have the factory electrical supplement 8A, but no scanner, so I didn't get far. To start with, the antenna mast is gone and the motor isnt working, but I was able to get stations. It was originally working only thru the RH rear speaker, but weak. I knew the LH rear amp was bad and the speaker was missing, but both fronts were untouched, just not working. Tonight I removed the LH front module to take a look. The plug was stuck together because contacts were green, so I cleaned them and plugged the module back in and turned the radio on. The RH rear speaker worked for a few minutes (like it did before) , and still nothing from the LH or RH front, then a "poof" and no sound. All the radio does now is show 1:00 and will take a CD in and eject it, but no sound or radio station on the screen (oh, and all the green lights still light up). If I leave the radio on and turn the key to off and back to ACC, the radio screen is blank until I turn the radio off, then the 1:00 comes back on, but no sound or motors run in the head. Both fuses are ok. Is there a 3rd fuse somewhere? Anyone seen this before? I even tried 2 other speaker/amps and no sound or radio station on display, just 1:00. I like to keep things original, so I'm hoping this is something I can troubleshoot and fix without alot of expense. I have 6 spare speaker amps already.

 

I think there are some people on this forum that make a career out of trying to keep Bose systems working! Good luck! Sounds like you've found a fine new hobby!

 

 

I do not know the year of your car and there any differences from year to year.

In general, the radio head unit in the dash has the ***** and buttons you turn and push. The actual electronics are under the dash in a 91 and 92, and it was moved into the storage compartment behind the passenger seat in 93 IIRC. Each speaker has its own amps, which are prone to fail.

Generally the amps have some resistors and capacitors that fail, and if you are good with electronics you may be able to repair them. I think you will be lucky to fix the ECM - the electronics module- as I do not think the schematics are readily available. Nor does GM or Bose provide and info on the radio head.

Good luck, and fill out your profile so we know what type of car you have and where you are located.

 

Unless you are dead set on staying factory, ditch the crappy Bose system and have an aftermarket system installed, or do it yourself.

I work on eletriconics for a living, and I wouldnt begin to mess with one of these systems. The pain, headache and time involved is just far to costly... Only to have a sub-par system at best, when you are finished.

 

If you go to the top of the General Discussion forum you will see the sticky with the "ultimate c4 diy thread" - in there you will find a link to the archives with info on how to repair the speaker amps. If you decide to repair the amps yourself be aware you will need a good soldering iron not the cheapo stuff you get in Home Depot or Radio Shack. If the radio unit or the tuner controller is bad - contact Dr. Dons -
http://www.doctordons.com/corvetteradios.htm . But in the end you will still have 90's sound tech.

I was going to keep everything original too until I realized how much time and work I would save by replacing everything. I got a Pioneer radio with HD radio and a USB input plus two new speakers, wiring and install kit (from Crutchfield), two speakers from Amazon and used standard speaker enclosures (from Ebay) all for about $300.00. I installed it myself over the course of a few days and it sounds good. I have a 32gb flashdrive with a couple thousand songs plugged into the USB drive and I no longer lug any CDs books around.

Good luck with whatever you decide to do!

 

Thanks all for the tips on my new hobby. The car is a 1991. I like the original look, but I'm getting the feeling I will have to replace all that crap with a nice looking aftermarket setup, and the $300.00 one described above sounds like a good suggestion. I'm ok with electronics, and I have a few good junkyards around full of speaker amps (being between Flint, Lansing, and Detroit), but I really don't want to invest alot of time and money in a system that will sound crappy when I'm done. So I guess I am going to replace it all, anyone know where I can get a harness adapter and what do I do with the original speaker wires, can I reuse all that original harness?Any pics anywhere? I'd be happy with one unit that is powerful enough to run all the speakers in their original enclosures, too, I don't need to blow the back hatch off the car. Thanks.

 

Thanks, good suggestion, done!!

 

You may want to consider swapping out the head unit and CDM and installing a double din aftermarket radio. If you have access to junk yards in your area, you should be able to pick up a bunch of amps (you find them in corvettes, mercedes and cadillacs and many others Bose equipped cars). You just need four total but pick up as many as you can find as its good to have spares. I bought my radio at Best Buy and they installed it for about $125. With respect to originality, you may find their warranty useful as they will reinstall the original radio free whenever you want. You will need to pick up a few things that BestBuy doesn't have on the shelf to do the install. All are available from Crutchfield or Amazon. Here are the parts you will need to make the swap:
Metra Chevrolet Corvette 1990-1996 Turbo Pocket Kit - Metra 993051;
Bose adapter harness (Metra 70-1857 Tuner Relocation and Bose Integration Harness for Select GM Vehicles) and two PAC SNI-1 Noise Isolators (unless you like to hear the subtle "whine" of engine electronics).
I did this swap in my son's 1991 and my 1990 last year. Both work and still sound great. Although many (but not all) the C4 people on this forum are ready to rip out the original wiring and speakers, in my opinion there is no substitute for having four more amps in your car that are matched to your speakers. I have JVC radios (with front USBs and rear Bluetooth) in both cars and the Bose amps and speakers complement the radios perfectly.

 

I suggest that you call Dr. Don and talk to him first. His phone number is on his website.
This guy knows his stuff.

 

I ditched mine last night in my 87 with a 1 den from walmart and their install kit. But, you have to individually re wire to the bose speakers if you plan on keeping them, which i suggest because they sound nice. Tried to wire into original speaker wires in dash, didnt work. Had to run from each speaker to back of aftermarket radio to bypass original system. Sounds good now though. worth the effort ide say

 

Thanks, did you get any error messages after the installation? I ran across this service bulletin: #93-8C-107: AFTERMARKET RADIO MAY SET DTC'S 72 & 74 IN CCM (INFO.) VEHICLES AFFECTED: 1990-93 "Y" MODEL. And thanks for the junkyard suggestion, I went and picked up 6 of those amps with 5 speakers for under 15 bucks, now I just have to test them somehow without blowing a head unit???

 

 

Sorry, while it may work for now that is by no means a correct solution. With the way you wired that it will only be a matter of time before you blow the amplifier section in your aftermarket radio. However if you keep the volume low you may extend the interval before failure.

Regards,

 

I have not had the need to pull codes on the 90 or 91 since the radio installs. I can't imagine why there would be a message if the original radio head and CDM are completely out of the car. I was fortunate to have two vettes sitting around when I brought home some junk yard amps. They were easy to test in the 91 as I replaced the radio in that in August and the one in the 90 in November. If you have a buddy that has a c4 (91 or better preferred) with bose, see if he will let you test your amps out on his car. Easiest thing to do is use the right or left rear speaker housing and swap out the amps. I don't recommend pre 91 cars as they may still have the amps with the integrated harness which makes tougher to test. BTW, the rear amps are more powerful than the front ones but they are interchangeable. Suggest that you select the 4 loudest (rear) amps for your car. They will work fine both in the front and back with an aftermarket radio. Also, if you decide to install the radio yourself, understand that you will need to do some cutting behind the old head unit and you will get your fingers cut up pulling the CDM in your 91 out of the dash. That is what made it worth paying the $125 for Best Buy to do the install. If you are curious to see what an aftermarket radio looks like in the dash, you can see it in "My Corvette Photos" gallery.

 

Interesting, thanks. Here's the rest of the bulletin:


CONDITION:

--------- On the 1990-93 Y-car, Diagnostic Trouble Codes (DTC's) 72 and 74 may be set in CCM if an aftermarket radio is installed. "SYS" will be displayed in the LCD section of the cluster, and the DTC's will be displayed when the diagnostic mode is entered.

CAUSE:

----- With an aftermarket radio installed, DTC's 72 and 74 are likely set because the LCD and LED dimming lines to the radio have gone open circuit, because these inputs do not exist in an aftermarket radio.

CORRECTION:

---------- 1. Disconnect negative battery cable.

2. Remove the radio control head, following the directions in the Service Manual, Section 8C. This will allow access to the radio control head wiring.

3. Add 1 K ohm, 1/2 watt resistors as shown in the illustration. The resistors are available from a local electronics supply store, such as *Radio Shack. The resistors should be connected to a 12 volt ignition- switched circuit. For 1991 to 1993, there is an auxiliary power pickup in the console. For 1990, ignition circuit number 300 should be used. See Section 8A for wiring details.

4. Reinstall the radio, then reconnect negative battery cable. Clear the CCM DTC's as shown in Section 8D, and verify proper operation.

 

Well, I have faith it will work awhile, if not the stereo was cheap. Hahahaha. Two questions though, what would make the amplifier section blow? And what would be the correct way Dan? IF or WHEN it does blow. Sorry dont know much bout stereo stuff, just wired mine up and it works great. Lemme know thanx

 

Thanks, one more question. I re-connected the battery after a few days (and charging it up) and turned on the radio and it came on again and sounded good. I tried connecting another junk yard speaker and amp to one of the channels that needs an amp and turned it on and it didn't work, like before. Do these heads or main amps reset themselves after a certain waiting period?????????

 

I have a 92 c4. I have had the stereo rebuilt and all of the amplifiers, it seems like I am not getting the proper sound from the front speakers. there is no f/r adjustment only l/r.

 

Here's my radio Bose fix..