How to Install a Treo 600 Custom Cradle in a 1999 Saab 9-5

May 2005

I have been meaning to do this project for a while, finally got to it.




- No visible wires, etc. Phone simply plugs into the cradle.
- Power to the phone when in the cradle
- Works with Saab Telephone mode for the OEM stereo system
- Works with Built-In Saab Mic
- Cradle securely mounted on the dash, no suction cups, etc


Saab 9-5 WITHOUT the ON-STAR system. If you have an ON-STAR system there are other steps that you have to do. Please see references.

Saab 9-5 WITH a pre wired microphone and car phone jack. I have a U.S. base model 9-5 (not SE) and it had everything that was needed. You can check if you have a microphone by taking off the plastic inside roof header where the map lights are. There is one screw that you have to take off. On the drivers side towards the front, there will be a microphone.

Treo 600 (I know, kind of an assumption)

Itrimming Treo 600 Cradle with Auto Power Adapter

Drill, Drill bits, Counter Sink Bit

Radio Shack 3/32 stereo plug

5 Minute Epoxy Glue

Soldering Iron and Solder

Some spare stranded wire

Saab car phone adapter harness

Radio Shack Toggle switch

Jeweler’s Screw Driver Set.


Medium Soldering, Electrical, Drilling.


1) Saab car phone adapter harness from Saab USA, Part number 400-108-130. Please make sure this is the correct one for your car.

2) The cradle from itrimming (see references) with the car auto adapter.

3) The 3/32 plug adapter and toggle switch from Radio Shack

4) Any of the other items (also see description)


The 3/32 plug adapter has to be rounded-down to fit in the Treo. You can use a grinder, but you could do it with a dremmel, etc.

- Remove the plastic screw on cover and discard.
- Grind down the base of the plug above the threads until it fits nicely in the Treo all of the way.

The car adapter has to be modified to be used. This will be used to power the phone.

- Take the adapter apart by removing the screw on cable guide on the plug end and take the adapter apart.
- Remove the metal plug parts and spring.

The cradle has to be modified to add in the plug. The cradle already has the bottom connector, but the plug needs to be added because there is no audio-out on the Treo 600 bottom connector. The Treo 650 does have this feature, but that is for a later time.

- Take the 4 screws out of the back. You will need a jeweler’s driver set (Radio Shack) to do this.
- You can discard the desk rest piece and the support piece.
- Carefully mark where to drill a hole for the male plug adapter.
- Drill a 5/32 hole and test the location buy putting the plug into the Treo and the placing the Treo in the cradle. It should come close to the drilled hole. You can adjust the hole a little bit.
- Remove the larger socket from the cradle by taking out the 4 screws in the PCB.
- Use a soldering iron and remove the USB cable.

Now we have to take a look at the wiring diagram. Here is how it should work.

Saab Cable Treo 600 Pinout

1 12V Power RED 14,15 (Choose 1, 2) (adapter)
2 12V Switched Power RED/BLACK 14,15 (Choose 1, 2) (adapter)
3 Microphone Ground GREEN GND
4 GROUND BLACK 6,12,13
5 Telephone Mute YELLOW N/A, Ground via switch
6 Rheostat
7 Telephone Line Input Grey/White Middle 3/32 plug
8 Telephone Line Ground Blue/White GND
10 Microphone Output Grey/Brow TIP of 3/32 plug

Saab Overhead Console Mic Settings (I did not change and seems to work)

1 output high
2 output low
3 Microphone Ground

DO NOT connect 12v to the Treo. Melting time. Make sure to use the adapter to do this. Connect / solder power through the power adapter.

Connect the wiring diagram as above. Please make sure that the 3/32 is soldered correctly. The middle solder point it the tip, the top solder point is the middle. Check with ohm meter to make sure. The rest can be soldered on the PCB. Please take your time and check your work. Check for shorts, etc.


Remove the climate control unit in the Saab. Do this buy using two jeweler’s small flat head screw drivers along with some soft cloth. Put the soft cloth against the dash on each side and carefully pry out the unit. It should come out pretty simply.

Locate the female for the harness. Pull up the top of the female cap, this comes up about three quarters of the way up and stop. This is a lock for the male. You may need a small crew driver to help with this. Insert the male plug and push the lock down, it should go all the way.

Plug the phone in the cradle and the 3/32 plug. Activate the switch and TELEPHONE should appear on the SID display even if the key is off. This puts it in “telephone” mode. Place a test call with the Treo and test out vol. You will probably have to turn the vol all the way up on the stereo.

This should simply work. The one thing that I have found that the line output on the Treo is a bit low. I will probably put a 2x amp in line when I get a chance.

You can adjust the default vol level for the phone with the following procedure.

1) turn the radio off (push the vol button)
2) Hold down the Weather Band button and Turn the radio on
3) Seek to the telephone vol
4) Set to desired amount (I had to max)
5) Turn the Radio off


One way to secure the plug is to plug it in the Treo, Plug the Treo in the cradle. Epoxy the back side of the plug to the cradle. Do the same for the switch. Locate a desirable location for the switch on the cradle and epoxy in place.


One place to mount the cradle is to use the unused button location just left of the radio stack. Remove the SID display. Remove the two blank buttons. Drill a hole in the cradle for a bolt that will run from the cradle through the button holes. Secure the cradle by using a large toggle nut, a drywall screw and a small piece of wood, or byt using a small metal piece with a threaded hole. Make sure to place some sort of dash protector on the back of the cradle. I used some plastic electrical tape. Make sure to put the back of the cradle on before mounting. Make sure to run the cables from the back of the cradle though the dash hole and plug in the Saab harness. Test after mounting.


Replace the SID and Environmental display.


The Treo will not ring to speaker with the plug in. Try out and purchase the Toysoft, FREEDOM software. This will have the incoming call ring the speaker even though the plug is in.

The output of the TREO seems to be low for the Saab stereo amp. You may want to put in a low end amp in between line out and the Saab harness.

Make sure to use only one of the power supplies, either switched or un-switched. Keep in mind that there is a power adapter in line.


The cradle and adapter are about $15
The Plug and the Switch are about $5
The Saab harness is about $20


No Treo

With Treo


Location to purchase Saab Harness

Location to purchase cradle and power adapter

Location to purchase plug and switch

Treo 650 Pinout Reference

Another SAAB 9-5 Mounting Project

Toysoft Freedom Software