: Problem with bose in 99 sls

11-13-08, 09:38 PM
The Bose in my 99 SLS has been acting a bit strange lately.

Some days it plays only out of left side then when I mess with the balance switch the right comes back. Some days it is the right that plays until I mess with it.

Today the HU was on and the display was acting like it should but I had no sound at all. I pulled over, shut off the car, restarted it and the radio was working fine once again.

If the only problem I had had was today, with no sound at all, I would almost say it could be a relay for the amp, but with it only playing one channel or the other at other times I am not sure where to go with this. Any suggestions?

Should there be any codes for a problem like this with the stereo?

11-16-08, 11:49 AM
I have a similar problem... Sometimes when I start my 98 SLS, I don't have rear audio until I mess with the fader. Some times when I turn the car off, and the radio is on RAP, I loose rear audio... Some times when I start the car, the right front door speaker had distorted audio coming out, some times not. It seems to be hit and miss with it, and it never does it when I want to prove it.

11-16-08, 08:15 PM
Maybe someone will chime in with some kind of troubleshooting or suggestion of what to replace.

11-19-08, 09:40 AM
my bose in the 99 SLS just stopped playuing CDs for no apparent reason.. ive never had any problems with the fading and whatnot tho so idk..

12-05-08, 05:31 PM
Maybe someone will chime in with some kind of troubleshooting or suggestion of what to replace.

Don't know if this will make you feel any better, but I've had some of the same problems with a 99 STS. Three time (I think) balance was all the way to the left, but the problem went away instantly when I adjusted the balance--even though it read centered. Once, the radio completely died and just like you, I stopped, turned off the ignition and all was fine when I restarted.

After studying the schematics, all I can say is that the Bose system is rather goofy. The only audio connection between the head unit and the amp [seems] to be a simple fixed high level (not powerful, but "high" as opposed to low level that requires shielded cable) for left and right. The head unit communicates balance, fade, volume, tone, etc. info to the amplifier via the serial communication line. All of the speakers are connected only to the amp; not the head unit. In a way it makes sense, but combined with the 2 ohm speakers, it makes for an expensive, all-or-nothing aftermarket replacement. At least it's the best sounding factory system I've ever heard, even if the cheap, uncoated paper cones in the woofers make the bass a bit muddy compared to "better" speakers.

If I had to guess that the cause of the problem, I'd say that it's a serial communication problem that may not have anything to do with the head unit or the amp. I say this because of some rather strange behavior I've been noticing with my "weak" steering position sensor. On rare occasion and ONLY with a stone-cold car and only in certain weather, I'll the a single bong and "Service Stability System" message. I've also noticed that if I've left the garage (headlights will be on) on a nice sunny day and the headlights don't turn off rapidly, I'll get the bong and message. It's rather like one sensor error slows down or otherwise affects the serial communications. Also, in history (but never active) I find a few serial communication errors with various modules even though I've never received any other warning from the DIC and no service indicators have illuminated. It's almost like the serial line gets cluttered or corrupted at times and I have a sneaking suspicion that the radio died when it lost communication with the RIM.

If the problems get worse or much more frequent, I'll start reworking all of the ground connections. From what I've been reading, such is pretty much par for the course for these cars as they age unless they came from Phoenix or Albuquerque ;)

12-07-08, 11:07 AM
It is really weird, I had these problems a few times over a period of a week or so and I have had no more issues at all. Electrical gremlins are a SOB to try to track.