This is the most frustrating repair I've ever had to do on my 9-5. Supposedly the dealer charges up to $2000 when the ACC throws an 08 code. I heard they fix the problem by replacing the entire heater box. I can understand why they don't dink around under the dash with this repair.
The symptoms of a broken stop arm and/or blend door are a clicking noise behind the dash, and no control of the temperature or venting on one side of the vehicle. This can be confirmed by pressing the "off" and "auto" buttons simultaneously on the ACC controls. The computer will check the system and any codes will show up as a series of numbers. An 08 code will a classic confirmation of a broken stop arm or blend door lever on the driver's side.
Once I had my code I got under the driver's side dash, removed the four Torx screws, OBD-II port, and plastic panel, this exposes the offending parts.
The motor, vent elbow, and blend door are located under the dash near the gas petal, behind the center console.
I started removing the screws holding the motor and vent elbow. There are about six of them and they are all hard to get at. You will also want to undo the wire harness on the motor and the sensor on the elbow.
Here are the parts to set aside
This exposes the blend door
I had a broken stop arm, but that soon became a broken blend door shaft when I started banging on it with a jeweler's hammer. Not my most brilliant moment, I admit.
I was unable to fix the the blend door arm as described on other online sites, so I set out to fix the arm my own way.
I started by lining up the broken arm and using jeweler's glue to set it back in place (super glue on the tip of a toothpick would work). I let it dry and then used a two part epoxy that hardens into a clear plastic to coat the entire shaft. I used the epoxy to build up several coats. By the time I was done the shaft was extremely rigid, possibly stronger than when it was new.
With the shaft fixed, I was able to focus on the part that started this whole ordeal. I had ordered a new stop arm from The Saab Site.
The stop arm goes on the end of the shaft between the box and the motor. I had to file down, and ultimately remove, the small plastic clip on the shaft.
This, along with some grease, made it possible to slide the new arm on the repaired shaft. Make sure you press from both the front and back of the blend door to keep from putting pressure on the repaired shaft.
You will want to move the blend door stop arm all the way down. Then turn the metal shaft on the removed motor so it looks like this, with the notches facing in this direction:
Hopefully you can skip the next step by matching my photo above, but I found this shaft position by taking the motor apart and turning the motor's shaft until it fit the blend door shaft before putting the motor back together again.
Once the motor was back together, and aligned to fit the blend door shaft, I reinstalled the vent elbow (after gluing the loose foam rubber) and reassembled motor, hooked up the wiring harness and sensor, and tested the ACC again.
No more 08 ACC error. My vents work and the temperature is correct again.
This repair isn't technically difficult, but it's a hassle because the area under the dash is tight and the blend door area is even tighter. There are a lot of tiny screws to remove and they don't go back easily.
I used a headband lamp to light what I was looking at while I was under the dash. I don't know if I could have done it with a drop-light or regular flashlight.