Electrical Crazyness
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Inside of each door accordian tube, inside the connector there, one of the wires is a serial data line. The pin/socket will come lose over time and cause the car to whack out as such if that connection goes bad. Bill Curlee has great pictures of the offending pin/socket in the tech section, posted numerous times.
Safety Car
Joined: Apr 2007
Posts: 3,640
Likes: 83
From: . New York
Thank you all for the great input. Jistari, you are absolutely right, just because it did not happen for a couple of days, it does not mean anything. I took it to the installer, who had ran all his own speaker wires, and had him disconnect the radio (it is still there, but not plugged into anything). Sure enough, the problem was still there and it is getting worse. However, I narrowed it down to some connection to the left door; the lights on the buttons come on and off, and was able to trigger the symptoms by gently pulling the hose that connects the door to the frame. Today I took it to our local Corvette expert, who will track the loose wire (hopefully). As to why change the radio in the first place, I agree; I never got to hear the original Bose, but I bet it sounded pretty good. I had no choice in the matter, the previous owner had ripped his nav/sound system off when he could not pay and the car got reposessed.
He'll definitly find it, there arent That many wires in there, and it will probably be a simple fix. More on the original Bose below.This answers a ton of questions for me. I have the original Bose stereo and this along with several other threads indicating terror after custom install, I am leaning towards leaving the original and just running the ipod adapter thru the existing CD changer in the trunk.
To be honest though, Im an old guy
(relatively) and the Bose sounds fine to me. Ive added a car PC and display to the system (just for GPS/Media storage/ and apparently have geek like tendencies) but I run the sound back through the Bose and it sounds great to me
Thread Starter
Cruising
Joined: Feb 2012
Posts: 10
Likes: 0
Dgrant, that was a great comment. I found the thread from Bill Curlee and that is exactly what happened to me. Unfortunately, I had already taken it to the mechanic, otherwise I would have tried that first. Ill post the results when the mechanic is done.
Le Mans Master
Joined: Feb 2003
Posts: 6,369
Likes: 73
From: The line waiting to see Santa Claus stretched all the way back to Terre Haute, and I was at the end, Indiana
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18
Sounds like ground issues. The area behind the radio has some key grounding points, and I would speculate that any modifications made to mount the new equipment may have compromised one or more. C5s are very susceptible to electrical gremlins associated with battery or grounding.
5th Gear
Joined: Jun 2011
Posts: 5
Likes: 0
From: Indiana
Disclaimer: I may not know what the heck I'm talking about. "Bus" in the following means communications bus (internal vehicle network). I have no proprietary knowledge of the C5's architecture, message strategy, etc. What follows is what seems most logical based on what I am familiar with. I do not work for any of the big three, and have not. I'm reasonably comfortable with embedded networks, however, and based on that, I offer the following.
I never got to see a comm bus diagram for the C5, but I'd bet it has a J1850 bus for most of the Comm needs (switches to module, in between modules, etc.). It may also have a CAN bus, which GM started heading toward in the waning years of the last century. It doesn't matter a whole lot - the two act about the same - J1850 was typically one comm wire with an RC between it and chassis ground. CAN is conceptually similar, but 25 to 100 times faster and seems to deal with noise a little better, IMO.
It's (J1850) reasonably good about noise in part because it tends to be slow (around 9k bits/sec, IIRC).
A typical architecture would have a low powered module dedicated to receiving the key-fob signal. The other modules on the bus (Inst Panel, Radio Head, PCM, whatever) may have had a sort of light-sleep mode, where they could be "awakened" by bus traffic. I'm thinking stuff based on Motorola 68HC05V8 might have had this capability available. (edit: other manufacturers made similar parts. Intel and Philips, for example)
Now, let's put some of these things together.
If a comm wire is connected to something that doesn't "fall asleep" to the same bus command, that device (such as possibly an aftermarket radio) might conceivably keep everybody else drawing power and the result would be a weakened or dead battery. In this case, the low battery could cause other symptoms and replacing it could appear to fix things for a couple weeks or months even. It's also possible that, if J1850, the aftermarket radio might be using a different variant of J1850 (speed, message format, and/or message content) that could cause some problems.
Disconnecting the comm wire from the aftermarket radio seems like a good first step to me.
But what about an intermittent short to ground on the comm bus? I wouldn't expect this to cause a drawn down battery, UNLESS, the short prevented the "go to sleep" command from being pushed out across the bus. Similarly, it may be possible that a shorted bus could interfere with the normal key-fob induced power-up sequence. If the message is corrupted - even partially - it's not going to go through.
Bottom line:
The thread makes sense to me. A loose connector (an "open" short) or short to ground seem very likely to be a part of this. The new radio also seems a possibility, and I'd be very surprised indeed if the two weren't related (I.E. did someone pull a door panel intending to get a good look at the speaker wires?)
I never got to see a comm bus diagram for the C5, but I'd bet it has a J1850 bus for most of the Comm needs (switches to module, in between modules, etc.). It may also have a CAN bus, which GM started heading toward in the waning years of the last century. It doesn't matter a whole lot - the two act about the same - J1850 was typically one comm wire with an RC between it and chassis ground. CAN is conceptually similar, but 25 to 100 times faster and seems to deal with noise a little better, IMO.
It's (J1850) reasonably good about noise in part because it tends to be slow (around 9k bits/sec, IIRC).
A typical architecture would have a low powered module dedicated to receiving the key-fob signal. The other modules on the bus (Inst Panel, Radio Head, PCM, whatever) may have had a sort of light-sleep mode, where they could be "awakened" by bus traffic. I'm thinking stuff based on Motorola 68HC05V8 might have had this capability available. (edit: other manufacturers made similar parts. Intel and Philips, for example)
Now, let's put some of these things together.
If a comm wire is connected to something that doesn't "fall asleep" to the same bus command, that device (such as possibly an aftermarket radio) might conceivably keep everybody else drawing power and the result would be a weakened or dead battery. In this case, the low battery could cause other symptoms and replacing it could appear to fix things for a couple weeks or months even. It's also possible that, if J1850, the aftermarket radio might be using a different variant of J1850 (speed, message format, and/or message content) that could cause some problems.
Disconnecting the comm wire from the aftermarket radio seems like a good first step to me.
But what about an intermittent short to ground on the comm bus? I wouldn't expect this to cause a drawn down battery, UNLESS, the short prevented the "go to sleep" command from being pushed out across the bus. Similarly, it may be possible that a shorted bus could interfere with the normal key-fob induced power-up sequence. If the message is corrupted - even partially - it's not going to go through.
Bottom line:
The thread makes sense to me. A loose connector (an "open" short) or short to ground seem very likely to be a part of this. The new radio also seems a possibility, and I'd be very surprised indeed if the two weren't related (I.E. did someone pull a door panel intending to get a good look at the speaker wires?)
Last edited by 50N40W; Feb 19, 2012 at 11:33 AM.
Thread Starter
Cruising
Joined: Feb 2012
Posts: 10
Likes: 0
Sorry I took a while for this posting, but I wanted to be sure. It was indeed the connector inside the accordion tube between the door and the car; the data cable there was the culprit, just like Bill Curlee explained in the tech section (thanks dgrant3830). The mechanic fixed it, I got the radio reconnected, and I've been driving without problems for the last couple of weeks. Thank you all for the great input.
