I have a 2002 Saab 9-3, the last year they made the hatchback. It's a fun car that fits all sorts of kids and things, and it has bells, whistles, and dials to make my inner geek happy.
This is the story of how I made myself even happier by creating an inexpensive auxiliary-in for the radio; in other words, how I hooked my iPod up to my 2002 Saab 9-3. My car was made for the American market, but one of the sources I read claimed that the radios are the same no-matter where the car was sold, so this could work for you wherever you are.
I'll explain the process in a number of posts, starting with... some background!
Wednesday, July 28, 2010
Background
Several people took the time to document their work online, and it is their experiences and ideas that allowed me to develop my own plan. Although each person's modification is a little different, all take advantage of one or both of the existing external inputs to the radio: the cd-changer input and the telephone input (which is used by GM's On-Star system in my car).
We'd all love to use the cd-changer input since it's made for playing music, but the radio won't switch to it unless you connect a Saab cd-changer, or a microprocessor that mimics one (see the late, great, tragic device created by Carl Levine at Granite Embedded). So, unless we're very good detectives with microprocessor experience, that leaves us with the telephone input.
The first modification I read about was Seth Evans' (website no longer online, but see David Muir's page for archived copies). He found that it was easy to force the radio to play audio from the car's telephone input because, unlike the cd-changer input, all you need to do is connect a special "tel-mute" connection to the electrical ground. He opened up the radio and soldered a 1/8inch jack directly to the telephone inputs, and a switch between the ground and the "tel-mute" connection. Success!
The downside of this was that the telephone inputs don't produce full-range sound (apparently it sounds a like the sound is going over a telephone connection, with little bass), it's not stereo, the radio's tone controls are ignored, and in the end somehow the wiring short circuited inside Seth's radio and killed the unit!
Showing excellent character, Seth tried again with a new radio. He found a way to make all the same connections outside of the radio using a handy wiring harness in the passenger foot well. In some cars this connector has all of the telephone inputs and logic you need, and Saab will even sell you a wiring harness for it. I believe in my car this wiring harness is connected to the On-Star system.
David Muir has written a wonderful guide for a similar modification based on Seth's work, and he's given us lots of details and background information. I really owe him a great deal for organizing this information and presenting it so clearly.
I wanted to have better quality sound than it seemed you could get with the telephone connection, so I was really excited when I read what German Alvarez had done. He realized that we could bypass the low-fidelity, mono telephone input circuitry and use the cd-changer input to begin with. The trick was to connect the higher quality audio signal to the radio's telephone circuits at the last possible moment. He did this by opening up the radio, cutting a few circuit board traces, and making two tiny connections. This disables the cd-changer inputs, and the tone controls are ignored since the radio still thinks it's in telephone mode, but now the sound is high-fidelity and stereo! German created wonderful little circuits that complement an iPod car adapter and automatically switch from iPod to phone calls--which allows him to keep the telephone function.
So from all of this, I developed my own plan...
We'd all love to use the cd-changer input since it's made for playing music, but the radio won't switch to it unless you connect a Saab cd-changer, or a microprocessor that mimics one (see the late, great, tragic device created by Carl Levine at Granite Embedded). So, unless we're very good detectives with microprocessor experience, that leaves us with the telephone input.
The first modification I read about was Seth Evans' (website no longer online, but see David Muir's page for archived copies). He found that it was easy to force the radio to play audio from the car's telephone input because, unlike the cd-changer input, all you need to do is connect a special "tel-mute" connection to the electrical ground. He opened up the radio and soldered a 1/8inch jack directly to the telephone inputs, and a switch between the ground and the "tel-mute" connection. Success!
The downside of this was that the telephone inputs don't produce full-range sound (apparently it sounds a like the sound is going over a telephone connection, with little bass), it's not stereo, the radio's tone controls are ignored, and in the end somehow the wiring short circuited inside Seth's radio and killed the unit!
Showing excellent character, Seth tried again with a new radio. He found a way to make all the same connections outside of the radio using a handy wiring harness in the passenger foot well. In some cars this connector has all of the telephone inputs and logic you need, and Saab will even sell you a wiring harness for it. I believe in my car this wiring harness is connected to the On-Star system.
David Muir has written a wonderful guide for a similar modification based on Seth's work, and he's given us lots of details and background information. I really owe him a great deal for organizing this information and presenting it so clearly.
I wanted to have better quality sound than it seemed you could get with the telephone connection, so I was really excited when I read what German Alvarez had done. He realized that we could bypass the low-fidelity, mono telephone input circuitry and use the cd-changer input to begin with. The trick was to connect the higher quality audio signal to the radio's telephone circuits at the last possible moment. He did this by opening up the radio, cutting a few circuit board traces, and making two tiny connections. This disables the cd-changer inputs, and the tone controls are ignored since the radio still thinks it's in telephone mode, but now the sound is high-fidelity and stereo! German created wonderful little circuits that complement an iPod car adapter and automatically switch from iPod to phone calls--which allows him to keep the telephone function.
So from all of this, I developed my own plan...
The Plan
I wanted a simple solution, like Seth and David's, but I also really liked German's ideas of using the cd-changer inputs to get higher quality sound. So why not combine the two ideas? I also wanted to make as many connections as possible outside of the radio, I thought that the connections would be easier to make and more reliable.
So, the plan is to route sound from an 1/8" audio jack to the cd-changer wires on the radio's cable harness, and also connect a switch between the "tel-mute" and ground wires, again, on the harness, not inside the radio. Inside the radio I'll do exactly what German did, re-route the cd-changer to the telephone input. I found a lovely hiding place for the jack and the switch (picture forthcoming), so I'm not worried about making it look good.
The caveats: This disables my On-Star system. At the least I won't be able to hear it. However, GM hasn't supported the (analog) cellular hardware my Saab has since 2007, so no real loss. I'm losing my capability to use Saab's trunk-mounted cd-changer. Finally, to play from the iPod, the radio will be in telephone mode, which causes it to ignore the tone controls and it won't play quite as loudly.
So, the plan is to route sound from an 1/8" audio jack to the cd-changer wires on the radio's cable harness, and also connect a switch between the "tel-mute" and ground wires, again, on the harness, not inside the radio. Inside the radio I'll do exactly what German did, re-route the cd-changer to the telephone input. I found a lovely hiding place for the jack and the switch (picture forthcoming), so I'm not worried about making it look good.
The caveats: This disables my On-Star system. At the least I won't be able to hear it. However, GM hasn't supported the (analog) cellular hardware my Saab has since 2007, so no real loss. I'm losing my capability to use Saab's trunk-mounted cd-changer. Finally, to play from the iPod, the radio will be in telephone mode, which causes it to ignore the tone controls and it won't play quite as loudly.
Radio Modification
Following German's photos I scratched out circuit board traces with an X-ACTO knife between the left and right channels of the telephone line-in (labeled "TEL-L" & "TEL-R"), and, perhaps needlessly, between the cd-changer line-in and the preamp (these are labeled cd-accessory: "CDAC-L" & "CDAC-R"). I think this step may be unnecessary since we're going to cut those on the radio's wiring harness anyway.
To re-route cd-accessory to telephone-in I added a couple of tiny wires (in the picture, the signal goes from right to left). Of course, this is your best chance of bricking your radio, so be careful and use as little heat as possible! Because I was feeling paranoid, I surrounded my little wires with heat-shrink tubing, just to make sure that there were no short circuits.
Now I had to do the wiring outside of the radio to see if it worked.
To re-route cd-accessory to telephone-in I added a couple of tiny wires (in the picture, the signal goes from right to left). Of course, this is your best chance of bricking your radio, so be careful and use as little heat as possible! Because I was feeling paranoid, I surrounded my little wires with heat-shrink tubing, just to make sure that there were no short circuits.
Now I had to do the wiring outside of the radio to see if it worked.
Installing the switch and jack
I wanted to put the jack and the switch someplace out of sight, and I was hoping that this little cubby underneath the climate control panel would pop out and let me work on it. It did! Even better, the top turns out to be a flap, which makes it super easy to work on. You can see the installed switch and jack in that flap here,
Note that, for some reason, I thought it would be more convenient to put the switch in the rear of the cubby, behind the jack. I'd put the switch in front next time around.
To make sure they didn't come loose, I added a little epoxy, and then soldered a couple of wires to the switch, and an audio patch cable to the jack. It's easiest later if you choose an audio cable that can easily be split into a left and a right channel. These cables have to travel behind the climate control panel and reach to the back of the radio. After I took the following picture, I wrapped the cables so they'd stay together.
Note that, for some reason, I thought it would be more convenient to put the switch in the rear of the cubby, behind the jack. I'd put the switch in front next time around.
To make sure they didn't come loose, I added a little epoxy, and then soldered a couple of wires to the switch, and an audio patch cable to the jack. It's easiest later if you choose an audio cable that can easily be split into a left and a right channel. These cables have to travel behind the climate control panel and reach to the back of the radio. After I took the following picture, I wrapped the cables so they'd stay together.
Wiring Harness Modification
Now it was time to connect this stuff up to the radio. I carefully checked the radio's pin-out, which is on a sticker on top (check out those coffee stains!).
After getting set so I wouldn't solder anything to my steering wheel . . . I prepared to cut back the cover on that wire bundle. The switch's wires get connected between "TEL MUTE" and "GND"--you don't want to disconnect these (especially the radio's ground!) so I carefully removed just some insulation from the two wires. Then I cut the "CD GND" and "CD IN" for both the left and right channels. We're going to connect our audio cable to the wires going into the radio, so I stripped those ones. You can see all of these wires in this picture, but you may need to look carefully to see the bare spots on the "TEL MUTE" and "GND" wires (brown and black).
Then it was just time to slip on some heat shrink tubing, solder everything together, electrical tape where you couldn't heat shrink, and you should get something like in the picture below. Yes, the connections to the switch do look hokey.
Then it was just time to slip on some heat shrink tubing, solder everything together, electrical tape where you couldn't heat shrink, and you should get something like in the picture below. Yes, the connections to the switch do look hokey.
Does it work?
Yes, it works great! I use a Griffin AutoPilot to charge the iPod and give me an easy to find play/pause button. The AutoPilot has an adjustable gain control (high or low), which I find handy. I've only heard the radio distort once, and I was able to switch the gain to low. With this the sound is plenty loud enough for me (some people found that the radio's telephone input couldn't go as loud as they liked).
When I first installed this I even tried playing the same track off of a cd and the iPod to see if they sounded similar. Given that I had to fiddle a little bit to switch back and forth, I couldn't tell any big difference. I can hear the difference in sound from mp3s that have very low bit rates, so I think this means that modifying the radio was worth it.
It's worked for over a year now, even while my iPod seemingly died and was revived (hint: if your old iPod clicks when it starts up and then reboots, you don't need a new iPod). I posted this because it's straightforward (though you need to know how to solder), cheap, and might just work great for you too!
When I first installed this I even tried playing the same track off of a cd and the iPod to see if they sounded similar. Given that I had to fiddle a little bit to switch back and forth, I couldn't tell any big difference. I can hear the difference in sound from mp3s that have very low bit rates, so I think this means that modifying the radio was worth it.
It's worked for over a year now, even while my iPod seemingly died and was revived (hint: if your old iPod clicks when it starts up and then reboots, you don't need a new iPod). I posted this because it's straightforward (though you need to know how to solder), cheap, and might just work great for you too!
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