The amp is a problem on the sport sedans. You can buy a used amp at goldwing saab 1-800-saab-137 or call about having it rebuilt at Pioneer- part number 12800531 and phone 1-800-553-3756.
Expect to pay between $150 and $300 for a used or repaired unit. If you are in a pinch, you can bypass the fiber optic cables (by connecting them together. Make sure you label them to what port they go into the connector. If you switch them the radio will not work after assembling it.
The wiring to the module also has some large orange shielded fiber optic cables. Please note the input and output (arrows on connector) and mark the cables accordingly for installation. Take the cables out and insert one cable in the end in a small piece of vacuum line, and the other cable in the other end- forming a loop. Basically you are bypassing the module. Expect the door speakers to stop working until you get a new amp. The new amp will work as soon as you put it in. You will also need to have it "added" by a dealer to make sure you don't have any intermittent issues later.
If the system works after bypassing the Amp1, you know you have found the correct module which has failed in the O-bus. (Any of the modules in the O-bus will cause the symptoms you describe- Onstar is the next module which fails most often.)
You sound a little reluctant to loop the fiber optic cables. It is really not that hard. If you have already removed the amp, the looping of the cables is not a big deal. Just be sure to label the cables with arrows so you install them correctly. The optical cables need to face each other and touch to get a good signal- it will make sense when you get it taken apart.
As far as the battery, it is common for them to have a cell die and cause the car not to start. If you measure the battery voltage as 10 volts after charging for a bit, it has a dead cell. A load test will confirm the battery. Generally the saab batteries will only last about 4 years. Autozone can test the battery to verify the condition.
Let me know if you need more clarity,
Glad to hear the battery was the cure for the starting problem.
As far as the Amp- yes, it is the two orange cables connected to the amp with the wiring connector- no need to remove the cover. The fiber optics will held in two connectors- one comes out of the main connector, then there is a smaller connector. Use some tape or a marker to not the locations of the cables before removing.
When your connect the ends of the fiber optic cables, take care to not bend the cable too sharply. This means don't force a 90 degree turn, but smooth transitions. Too sharp of a turn can damage the internal optics and prevent signal transfer. The fiber optics need to feed into each other by placing the two "finger" ends together for light to flow through to the next module. (Similar to how in the movie ET he would touch fingers. There is a good chance one of the optic ends will be glowing- do not look into it.)
If bypassing the amp doesn't allow the radio to work, you will have to do the same with the On star unit- it can bee seen if you lay on your back in the trunk and look up- middle of the rear shelf.
Thanks for the update. Let me know if I can help clarify anything for you.
Curious how things are going.
If you don't have the money for the amp, you can simply leave the fiber optic bypass in place to allow the system to operate. The only real symptom is the front door speakers will not work.