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Mark N
Mark N, ASE Certified Technician
Category: Car
Satisfied Customers: 200
Experience:  Saab Master Technician, GM Technician, 30 years experience.
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2003 saab 9-3 radio wont turn on and turn signal sound

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2003 saab 9-3:

radio won't turn on and turn signal sound is mute. This has happened a couple of times in the past but "fixed itself".
Hello and welcome!

I'm working on the assumption that this is a 2003 9-3 sedan. If it's a convertible, please let me know, as that would be a different animal.

Anyway, these symptoms usually point to a bad amplifier, or "AMP 1" as Saab calls it. It's located under the driver's seat, and is accessible by running the seat all the way forward, and the cushion up, and work from the back seat. You may be able to just look at it and see rust/moisture damage.

The radio sound and all the other sounds such as the turn signals, key chime, etc. are sent out on an fibre-optic network called the "O-bus", and broadcast through the audio system speakers. This amp is on the O-bus. If there's a break anywhere on this bus, none of the modules on it will communicate.

A dealer would be able to run a test with a Tech 2 scan tool to determine where the break is. The amp I mentioned above is the most common problem, but they're VERY expensive, so I would get the car scanned to verify the fault before throwing parts at it.

Hope this helps! Thanks for checking in with us!
Customer: replied 7 years ago.
Hi Mark;

Would a bad amp prevent the radio from turning on and showing up on the dashboard display?

Hello again-


Yes, this would cause no info to be displayed on the dash, also. This is all info that's communicated over the O-bus. Again, ANY break on this bus would cause these symptoms, so it's best to have it checked.

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