Bose Amplifier Replacement (RPO UX9) on 1999 Seville STS

Kaline · #1 (**permalink**) 06-01-09, 12:52 PM

I'm having an issue with the Bose stereo on my 1999 Seville STS where the front speakers will emit a static-like noise during low frequency response (bass) on the front channel only, making the speakers sound "blown". However, it is an intermittant problem, and sometimes the stereo sounds great (therefore, I think the speakers are OK). Also, it varies between 1 speaker acting up to all 3 (both front doors and center dash). This leads me to believe it is an electrical issue. The rear channels sound great and are not affected.

I replaced the radio with a used, tested OEM one of the weekend: the system behaves the same. So, I think it might be the amplifer. My questions:

1. Where is the amplifier (RPO UX9) on a Bose-equipped vehicle?
2. How hard is it to replace?
3. Is this a common item to go bad?

Any information is appreciated. Thanks!

Kaline · #2 (**permalink**) 06-01-09, 01:17 PM

A friend of mine was able to answer the question for me: it is located behind the rear seat back. Attached are instructions from the GM Online Service Manual to replace it. Cheers! Hopefully this fixes my issue!

drives99caddy · #3 (**permalink**) 09-06-09, 04:50 PM

Hey, I can't view the pdf about the amplifier. I can view the other two pdf's about the seats. Any ideas?

ryannel2003 · #4 (**permalink**) 09-06-09, 05:01 PM

Yeah the PDF doesn't work for me either.

00 Deville · #5 (**permalink**) 09-06-09, 05:46 PM

All 3 of them opened up for me... I'm using Firefox browser opened with Adobe Reader. Send me a PM with your Email address and I will try to Email you a copy.

N*Caddy · #6 (**permalink**) 09-06-09, 05:49 PM

I would go first after the speakers, amplifier would be the last thing on my mind.
This is hwo your BOSE amplifier (a.k.a. RIM) looks like:

CadillacSTS2003 · #7 (**permalink**) 09-07-09, 07:31 PM

front door speaks are shot
common failure item

jcresciSTS · #8 (**permalink**) 09-07-09, 09:35 PM

yep, my driver door speaker doesn't even play but the every other speaker does...I only use my front speakers though anyways

Alert · #9 (**permalink**) 09-15-09, 05:24 PM

I own a '99 STS with a silmilar problem.

My front drivers door speaker emits a static sound. All other speakers work fine. I purchased two used speakers via ebay. I tried each new speaker in place of the "bad" speaker. Thny each made the same static noise.

So I opened up the front passenger door and connected the new speakers and they sounded fine. I then tried the original "bad" speaker in the passenger side and it, too, sounded fine.

So, obviously it's not the speaker. It has to be the amp or head unit.

I just disconnected the bad speaker and stopped trying to repair it after that. The system still sounds very good overall but it does bother me a little to know that one of the eight speakers is not working.

N*Caddy · #10 (**permalink**) 09-15-09, 10:38 PM

Quote:

Originally Posted by Alert

I own a '99 STS with a silmilar problem.

My front drivers door speaker emits a static sound. All other speakers work fine. I purchased two used speakers via ebay. I tried each new speaker in place of the "bad" speaker. Thny each made the same static noise.

So I opened up the front passenger door and connected the new speakers and they sounded fine. I then tried the original "bad" speaker in the passenger side and it, too, sounded fine.

So, obviously it's not the speaker. It has to be the amp or head unit.

I just disconnected the bad speaker and stopped trying to repair it after that. The system still sounds very good overall but it does bother me a little to know that one of the eight speakers is not working.

The HU can ONLY be blamed if this static sound is on all speakers form one side or in all speakers. Can be easily ruled out by switching to CD changer. If the noise is gone then yup is the HU. If the noise is ONLY in one speaker then is either the speaker or the RIM.

Alert · #11 (**permalink**) 09-16-09, 09:54 AM

If I recall correctly (this was over a year ago that I investigated this problem) the speaker sounded bad no matter what I played (radio, CD...).

What does "RIM" stand for?

(Also, I disconnected the six-CD changer in the center console and hooked up an iPod connection. It works very well and I love playing my iPod in my car)

After all this, I now have three good front door speakers sitting on a shelf in my garage.

N*Caddy · #12 (**permalink**) 09-16-09, 11:34 AM

RIM stands from Radio Integration Module. Is more like a historic name, because after ‘ ’96 the RIM function was changed to digital sound processing (starting with ’98 it also got an amplifier function). The RIM is pretty much the most important device in the sound system. Receives a constant low level two cannel audio signal from the HU and from the CD Changer. The RIM digitally processes this audio signal and customizes it for each speaker. For example when you set the DSP to “Drivers Seat” the RIM is the one delaying the sound for each speaker in such a way that it arrives to your years in the same time. So depending on the distance between each speaker and the driver seat the sound is delayed more or less to reach that point in the same time. Same is with the other effects like Hall, in that case the sound is overlapped few times (with a certain delay an less volume) to create the sensation off echo (hall effect). Also the RIM is the one doing the volume control and the EQ. Is also the one selecting between HU (i.e. Radio/Tape/In-Dash CD) and CD changer. This is why I mentioned in order to rule out the HU switch to CD changer (not In-Dash CD).

Above is the typical BOSE system diagram. The variation is ’97 and older Seville, and all Eldorado (up to ’02) had individual amplifier for each speaker, while Deville and post ’98 Seville had the amplifier incorporated in the RIM (the same with Catera). Observe the data lines. This is how the RIM and CD changer know what button is pressed on the HU. Including the volume control, when you turn the volume knob the HU does nothing to the volume, that information is send to the RIM (via the data bus) so the RIM adjusts the volume of the sound sent to the speakers. This is why you can insert your own audio signal between the RIM and HU (or CD Changer) and you got hard wired AUX input (already posted the diagram).
The non-BOSE systems have the amplifier incorporated in the HU (thus no RIM).

Perhaps I should have put individual lines for each speaker from the RIM so you don’t get the idea that the sound is the same in all speakers from one side or the other. IS NOT, the sound in each speaker is customized (either time delayed or level or frequency filtered). Also the Driver side speaker is the one receiving the chime (overlapped over the regular sound) and in case you have a SUB in the system the L and R channels are summed and the high frequency is removed.

Alert · #13 (**permalink**) 09-16-09, 12:23 PM

So, it seems I'd have to replace the RIM to get the driver's door speaker working properly. I went to gmpartsdirect.com and it didn't have anything for the part number listed at the start of this thread (RPO UX9).

What's the number for this part that can be used to look it up on the web (or gmpartsdirect.com)?

N*Caddy · #14 (**permalink**) 09-16-09, 08:03 PM

I believe '98 and '99 shared the same RIM. The '98 RIM P# is 25689911. Even if is not the same number it will still work and no need to program anything. Just look on E-Bay you can find one for something between $50 and $150.

Here is $49.97 (BuyItNow)
Here is $95.00 (BuyItNow)
Here is $125.00 (BuyItNow)

Personally I would recommend you the $49.97 one, LKQ is a pretty well known name, and shipping is decent.