technical diversions

a place to document my current project of connecting an iPod to a Saab 9-3 convertible with the factory audio system.

Monday, April 25, 2005

How to mod the radio

Many thanks to all the contributors, and the ones that tested this on their cars. After a few ones have done this, i think the document is ready to be posted.

Here is the link to it.

This document describes how to add an AUX input to the factory radio. This can be phono stereo 1/8 jack or RCA type. The input will be for a "line level" signal but a signal from the headphone jack of your player will work, just be careful with the volume level. Adding this input uses part of the circuits and connectors used for the external CD changer. After this modification the external CD changer cannot be used (or installed). The modification is reversible.

Seth describes a much simple way to modify the radio on this link:

During the development of my installation I tried to do what Seth did but it did not work for me. I do not know why. An important difference is that he is using the headphone output and i'm using the line level output. This is an open issue and my suggestion is to follow what Seth did and if it works for you, just stop there. If it does not work or you want to keep the onStar/Telephone interface working then you need to go all the way.


  • At 16 July, 2005 11:11, Anonymous Anonymous said…

    FYI: I just opened a Saab 9-5 2k2 HK stereo system looking for a way to wire in an Aux port.

    It -IS- possible, but the head unit must be completely dismantled, which is very doable.

    The FM tuner unit connects to the circuit board with a labeled (on the underside) L-Out, R-Out which is an unbalanced connection to the pre-amp.

    Cutting this connector and installing a switch via twisted shielded cables can bring this outside the head unit and give you a switchable AUX input. Flip the switch one way and you get AUX-in (the head will still show the FM station), flip it the other way and you get FM.

  • At 16 July, 2005 20:28, Anonymous Anonymous said…

    Any more details on this method (FM tuner for some of us who are not so technically savvy? Pics, diagrams, more detailed procedure would be greatly appreciated...
    I have a 2003 9-5.

  • At 17 July, 2005 12:32, Anonymous Anonymous said…

    If I could upload it to some site, to host it I would.

    I found the schematic for the 9-5 stereo on the net. It also bears out what I've found.

    Basically there is a "tap"/test point labled ROUT/LOUT under the FM/AM tuner that can be cut and a switch intererted between the now cut connections.

    This utilizes the TU/TEL inputs to the SN761029DL controller.

    The only caveat is that you MUST place a resistor in line on each channel to lower the current coming from your mp3 player or other device. The FM tuner spits out 1.5 to 2.5v -30 DB which is tiny compared to what most normal devices do.

    I placed a 1k resistor on both the inputs and this seems to work fine.

    It's not hard to do all of this, but you will have to COMPLETELY dismantle the head unit. The way it is built, this is not that difficult.

  • At 18 July, 2005 18:23, Anonymous Anonymous said…

    Unfortunately it sounds like too much for me. I am afarid I am going to scew it up.
    I would pay somebody to do it. I am on East Coast, NY/NJ area...

  • At 01 August, 2005 22:40, Anonymous Anonymous said…

    Can u please post pics of this operation! Thanks in advance!

  • At 02 August, 2005 13:58, Anonymous Anonymous said…

    Ok now I have dismantled the head unit and I can see the L out R out on the motherboard backside. Can u confirm that u just CUT the connection between the test point and the pin?

  • At 22 September, 2005 17:40, Anonymous Anonymous said…


    For an easier solution for 9-5's.

    No you cannot cut the test points, btw. That doesn't work.

  • At 29 October, 2005 13:10, Anonymous Anonymous said…

    Re: 9-3

    Does anyone know why he didn't simply put a switch on the inputs from the FM tuner?

    Are these not line/aux level inputs, like the 9-5 which uses 4.5 volts?

    If they are 388mV like the telephone inputs, you could just wire in an aux-in that would operate with FULL volume & tone controls, and a switch.

    One way, you would get standard FM, the other way would give you input from the Ipod?

    Is this not workable?



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