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Saul,
First, welcome to the wonderful, wacky world of MY 2003-2006 9-3SS audio systems.
Our motto: Why make it simple when complicated will do just as well.
First lets look at how your system is setup. The 2003-2006 9-3SS has between 30-40 control modules (of which about 20 something can have software updated via a Tech II and TIS with a security key) that communicate over 3 data networks. P-bus is the powertrain data bus. I-bus is the interior data bus. O-bus is the Optical bus. Each data bus has a different speed, topology, and media. The O-bus is what we are concerned with here so lets talk about it.
The O-bus uses fiber optic cable as its media. It has speed of 25 Mbs and has a ring topology. The system is setup so that if there is a break in the ring, communications stop and nothing on the O-bus will work. The fiber optic cable is orange in color and is about the size of 14 gauge wire. It should not be bent more that a 1 inch radius as it can break inside and cause intermitant failures. It can not be spliced. If damaged, it must be replaced as a complete cable between the two affected components.
Now lets look at players on the O-bus.
First up is the ICM (Infotanment Control Module). The ICM is the item in the dash that looks like the radio. IT IS NOT THE RADIO. It has no direct connection to ANY speakers. The ICM serves two main functions to the O-bus. First it acts as the master control for the O-bus that controls O-bus modules based on user input and request/info from other car modules. Second, it acts a gateway to the I-bus and I think the P-bus. I know it is the only place on the car the has connections to all three data networks. I also know if you remove the ICM, the car will not start.
Next up is the EHU(Entertantment Head Unit). The EHU has the radio tuner and an amplifer in it. The amp in the EHU controls the speakers in the RF and LF of the dash and smaller speakers is the rear deck. This module is present in the 7-speaker and 13-speaker systems. I don't know if the amp rating in the EHU is different for each on the systems. The EHU is located in the dash behind the A/C controls and the ashtray. The bottom of its cage is where the CDF(Compack Disc Front)or CDCF(Compack Disc Changer Front)resides.
Next is AMP1 (Amplifer 1). AMP1 controls both front door speakers and the center dash speaker. I BELIEVE it is sub-woofer type system and is tuned for low freq operation. AMP1 is convenently located under the LF seat on the outboard side. Leave a window or sunroof open or spill a drink in your lap and you have made a $1K part into a rusty paperweight. AMP1 is present with 7 or 13 speaker system.
Next is CDF or CDCF. It is located in the dash an plays your CDs. CDF is a single CD player and CDCF is a six CD changer. You can install a CDCF in place of a CD if you desire. You will need a Tech II and TIS with security key to do this operation
Next is AMP2(Amplifier 2). AMP2 operates the larger speakers in the rear deck panel. It is located in LR of the trunk behind the pull down cover that gives you access to the tail light bulbs. AMP 2 is only present in the 13 speaker systems. You can add an AMP2 to your 7 speaker system. Saab made a kit for about $500-$600. I don't know if the kit is still available. You can install it on your own, but you should have the component added to the network with a Tech II for best operation.
Additionally OnStar, NAV, and the CDCR(CD Changer Rear) are on the O-bus if equiped. Yes, you can have a CDCR and CDCF for a total of 12 CD capacity. I have only seen 1 CDCR and I don't think they are sold anymore.
So how does all this work. Lets listen to the radio. First, the user turns the system on and selects the station they want to listen to. The ICM sents puts this information on the O-bus. The EHU sees the request, sets the tuner to proper station, sends varying voltage its speakers it controls, then outputs sound info in data packet form on the O-bus. AMP1 and AMP2 also see the request from ICM, decode the data packet from the EHU and output varying voltage to their speakers.
Hope this helps,
Steve C
posted by 205.157.24...
, Sun, 12 Aug 2007 06:42:08
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