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Stereo/Cig lighter wiring problem

tim1

Well-known member
Joined
Jun 25, 2011
Messages
96
Location
Georgia
I put my GPS in the Vette the other day and while waiting for it to aquire sattelites the radio and GPS both shut off. I checked the fuses and found the radio fuse blew, so I unplugged the GPS changed it out as soon a I turned the key on it blew the radio fuse again. I am thinking there is a dead shorted wire between the radio wire and the cigaette lither wires. Anyone have any other ideas? Or have a wiring diagram for these underdash wires so I can try to locate the problem?
 
I forgot to mention it is a 93 with the factory stereo installed, and since I bought the car it has never had a lighter in the socket.
 
Cig lighter socket

I put my GPS in the Vette the other day and while waiting for it to aquire sattelites the radio and GPS both shut off. I checked the fuses and found the radio fuse blew, so I unplugged the GPS changed it out as soon a I turned the key on it blew the radio fuse again. I am thinking there is a dead shorted wire between the radio wire and the cigaette lither wires. Anyone have any other ideas? Or have a wiring diagram for these underdash wires so I can try to locate the problem?

All I can offer is my experience with my 95 coupe, which I think will be close to the same for your car. First, look for anything that may be at the bottom



of the cigarette socket. I just

1995 C4 Corvette 002.jpg

keep a small USB plug (Dollar Tree) in there to keep anything from falling in here and setting up a short. Also, my owners manual shows a separate wiring harness under the shift console and instructions for the relatively easy access to this harness. You could put an additional 12 volt socket in this line for complex electronics - which my manual does recommend. With this area now exposed, you can take a good look at the back of your cig socket and maybe even replace it or run a separate new circuit from this recommended harness.
Finally one last comment, although kept for generations now, the 12 cig socket is a lousy choice for an electrical connection. From my boating experiences, this antique set-up is prime for corrosion, vibration, and poor connectivity, and it just way too big for a simple 12volt hook up. The boating industry is still trying to use better hookups, but this hang-on from a long gone era persists. All the Best and have Fun!, John
 
Well I hate to bring up a very old post but I still have not gotten this fixed. Today I started taking things apart, unhooked the cigerette lighter and removed the fuze for it. I then put in a new 5 amp fuse for the radio, turned on the key and the radio came on for about 5 seconds and blew the radio fuze. I suspect it is the main ground for the radio system. Can anyone point me to the grounding location for the radio system so I can check to see if it is actually grounding? Or anyone have something else I might need to check?
 
Well I hate to bring up a very old post but I still have not gotten this fixed. Today I started taking things apart, unhooked the cigerette lighter and removed the fuze for it. I then put in a new 5 amp fuse for the radio, turned on the key and the radio came on for about 5 seconds and blew the radio fuze. I suspect it is the main ground for the radio system. Can anyone point me to the grounding location for the radio system so I can check to see if it is actually grounding? Or anyone have something else I might need to check?

you can check the grounds if you want. It won't hurt. But if the fuse is blowing then your problem is somewhere else. (5a sounds small to me would have thought it should be at least a 10a fuse). It may be time to replace the radio. Uless you can find a fault somewhere else.
 
I removed the stereo today and nobody in this town can hook it up to check the radio. So I put in a new fuse with no radio installed and turn on the ignition, the fuse did not blow which leads me to believe that the radio has given up the ghost. Time to try and find another factory Bose radio I guess.
 
I believe I've seen people post about places that refurbish radios, might be worth a shot rather than buying a new one.
 
Well I hate to bring up a very old post but I still have not gotten this fixed. Today I started taking things apart, unhooked the cigerette lighter and removed the fuze for it. I then put in a new 5 amp fuse for the radio, turned on the key and the radio came on for about 5 seconds and blew the radio fuze. I suspect it is the main ground for the radio system. Can anyone point me to the grounding location for the radio system so I can check to see if it is actually grounding? Or anyone have something else I might need to check?

Looking at the schematics, RDO 5 amp fuse only powers the factory Bose Reciever box located behind
the passenger seat in the storage bin.

The connector at the CDM with the Yellow wire is the 12 volts from the RDO fuse.

The Receiver box is the brains for the radio control head.

As for the cigar lighter fuse it has no connection with the RDO 5 amp. fuse.
The Receiver box also called the CDM is a high failure item. Used on E-bay from $50 to $100.

Disregard the red arrow in the photo below.

 
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Thank you ecss.... I took the vet to a shop and they want to install an aftermarket stereo. I have been trying to find the reason I keep blowing the 5 amp battery fuse and have been unsuccesful. If anyone can point me in the correct direction it would sure help me out. Someone on another site told me to jump the pink to yellow wire on the connector that plugs into the radio(there are two connectors). I am just not sure if this is what I need to try to see if the fuse blows and that would tell me the CDM is bad. So anybody that can help me test to see that the CDM is faulty please chime in. I hope to hear something soon so I can test it out this weekend. Again thanks for all the pointers.
 
Thank you ecss.... I took the vet to a shop and they want to install an aftermarket stereo. I have been trying to find the reason I keep blowing the 5 amp battery fuse and have been unsuccesful. If anyone can point me in the correct direction it would sure help me out. Someone on another site told me to jump the pink to yellow wire on the connector that plugs into the radio(there are two connectors). I am just not sure if this is what I need to try to see if the fuse blows and that would tell me the CDM is bad. So anybody that can help me test to see that the CDM is faulty please chime in. I hope to hear something soon so I can test it out this weekend. Again thanks for all the pointers.



Well I maybe giving you some wrong information because if it's the RDO Batt 5 amp fuse it makes no
sense what you are saying because that fuse is HOT AT ALL TIMES. If there is a short to ground on that
circuit, the fuse would blow as soon as you put a new one in. You stated it blows when you turn the ignition
On.

There are two RDO 5 amp fuses

There is a 5 amp RDO IGN fuse Yellow wire which is hot when you turn the ignition on and stays hot for 15 minutes after the ignition is turned off or until the door is opened. (This is used by the delayed accessories bus).
This is the fuse I assumed you were talking about since you said the RDO fuse blew when you turned the ignition On.

There is also a 5 amp RDO Batt fuse Orange wire HOT AT ALL TIMES used to keep the memory for the clock and radio presets powered when the ignition is OFF.
That fuse is also used by the Passive Keyless entry module.

Indication the 5 amp RDO Batt fuse is working. When the ignition is off you should see the time displayed in the radio control head LCD

So please clarify which fuse is blowing. :L It makes no sense if it is the RDO Batt fuse because as I said that
fuse has 12 volts on it at all times and if shorted would blow with the ignition Off.

Here are some schematics showing both RDO fuses and the Cigar fuse.




Not sure if this is a misprint but in the schematic below RDO IGN fuse is shown as 10 amp instead of 5 amp.
All the other schematics I posted show it's 5 amps.







 
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It is the radio bat fuse that blows within 5 seconds of turning the ignition on.
 
It is the radio bat fuse that blows within 5 seconds of turning the ignition on.


The RDO Bat fuse only goes to three places.
1) Radio Control Head
2) Radio receiver (CDM)
3) PKE module

On the back of the Radio Control Head are two connectors.
A 7 pin connector and a 9 pin connector.

On the 7 pin connector the color of the wires should be
1) Red
2) White/Red
3) Orange
4) Gray
5) Brown
6) Green
7) White/Green

From what I can tell, Pin 1 Red wire is the RDO Bat 12 volts input to the Radio Control Head.
The schematic shows the wire is Orange but it appears the service manual is wrong.

You need to either cut the Pin1 Red wire allowing enough slack so you can re-solder the wire or de-pin it from the connector.

Reconnect the two radio control head connectors.

******Make sure the disconnected Red wire does not short out on anything. You could wrap some
electrical tape around the pin). **************

Install the new fuse, turn on the radio and if the fuse blows the problem is in the CDM.
If the fuse does not blow the problem is in the radio control head.

The picture shows the tab on the connector that needs to be lifted before you can extract the Red wire.
The picture also has an arrow on the extracted pin that shows the locking pin tab that must
be depressed to extract the pin.

 
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Well bringing up a very old thread. I think I might have lost my mind, have not touched or been around to touch my vette since March. I wanted to try to do some of the troubleshooting today and cannot for the life of my even begin to remember where the IP Fuse Block is located. I feel like a real idiot posting this but I can't seem to remember where it is.
 
Just spoke with my neighbor and he remembered where it is located. Now to make the drive to do some looking at the stereo.
 
I just got done doing what ecss recommended and it still blew the fuse. His post states if the fuse still blows after unhooking the red wire it is the CDM that is faulty.
So my question is: Does the repplacement CDM need to be the same model number as the original? I located a couple but the model numbers do not match mine. Thanks for all the help.
 
I just got done doing what ecss recommended and it still blew the fuse. His post states if the fuse still blows after unhooking the red wire it is the CDM that is faulty.
So my question is: Does the repplacement CDM need to be the same model number as the original? I located a couple but the model numbers do not match mine. Thanks for all the help.

I would get the same part number CDM. There are two versions of the CDM. One for the Bose Gold and the other for the Delco.

Does your cigar lighter work now?

I'm guessing all of the 90-96 Corvette CDM's for the Bose Gold are the same and GM changed part numbers over the years.
 
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Yes the cig ighter is working. I did just like you recommmended with the wire and it did blew the fuse. Removed the CDM and replaced the fuse and turned on the Bose and it does not blow the fuse. My CDM is model 16178351, the CDM I found is out of a 90 model number 16178341. The guy said the differance is in 90-91 they were mounted under the hood. I want to be sure it will work before I just throw money out the window.
 
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Yes the cig ighter is working. I did just like you recommmended with the wire and it did blew the fuse. Removed the CDM and replaced the fuse and turned on the Bose and it does not blow the fuse. My CDM is model 16178351, the CDM I found is out of a 90 model number 16178341. The guy said the differance is in 90-91 they were mounted under the hood. I want to be sure it will work before I just throw money out the window.


As far as I know the 90-92 CDM's mounted on a plastic tray inside the car in the glove box area.
In 93 they moved it to the rear storage bin and is velcroed in place.

I have a used working 16178351 I can send you. You can test it and if it solves the problem you can buy it.

If it doesn't solve the problem send it back and you're only out postage. Send me a private massage if interested and what you consider is a fair price. Shipping would be about $5.00.
 
ecss, did you get my shipping info? It sounds like a deal I can't pass up.
 

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