Saab 9 5 Drivers Side HVAC Blend Door Problem

DIY Saab 9 5 Drivers Side HVAC Blend Door Problem Subject: DIY Saab 9 5 Drivers Side HVAC Blend Door Problem Title: How to fix the Blend Door
Overview:
This is a known problem where a plastic part fails that causes the Drivers (or passengers) side blend door to stop operating and will remain in the hot or cold position. To test if this is the problem, with the car running, calibrate the HVAC by pressing the AUTO and OFF buttons on the HVAC controls. If an 8 appears on the driver’s side (or passengers) this is probably the problem. The plastic stop arm is designed to stop the stepper motor for the blend door. When this fails the stepper motor has enough power to break the internal shaft from the motor to the door.
The fix is to obtain two plastic replacement parts and install.
Symptoms:
Air will not move to hot or cold when the other side does. HVAC calibration will fail with an 8 code on the side in question.
Mechanic level: Easy / Medium
Tools:
Basic torx, socket, Phillips tools
Time:
About 1 hour, much less if you have done this before
Parts:
12765865 Plastic replacement for inside failed shaft about $18 5334701 Plastic replacement for stop arm about $25
Procedure:
1) Remove the driver’s side under dash panel
a. Remove the 3 torx screws
b. Remove the plastic push holder from the panel, push in the center a bit, remove it
c. Pull out the panel slowly
d. Remove the two torx screws from the diagnostic terminal
e. Remove the panel from the car
f. You will probably find the failed stop arm falling to the floor
2) Remove the stepper motor, this is located next to the center of the car to the right of the steering column (states). You can identify it because it will have two white wire terminals that go to it. You will probably have to lay on your back and look to the left.
a. Remove the air sensor from the duct by carefully pulling back the two black clips. This is a pin like sensor that does not detach from the white wires
b. Remove the stepper motor wires but squeezing on the top of the white connector and remove upwards, but it aside
c. Remove the stepper motor be removing the two Phillips / hex head screws. The one on the bottom is easy, the one on the top will require a long Phillips, or you can use a ratchet with a 6mm socket.
d. Remove the stepper motor and put aside.
e. Sometimes the internal shaft will not fail, you can check this out by turning the yellow shaft that the stepper motor shaft was in. If it is very flimsy, it will have to be replaced.
3) Remove the failed plastic shaft
a. This will not remove directly and some other instructions say to remove the down assembly. I ended up pushing the shaft in and if fell out after a few operations of the blend door after reassembly.
4) Replace the new shaft and stop arm.
a. Put the stop arm on the replacement shaft and put back in. This cannot go in wrong, make sure the stop arm is in the opening to the top.
b. Turn the shaft arm and you can feel the blend door moving.
5) Replace the stepper motor
a. You may have to play with this a bit, but it will set in the new shaft.
b. Replace the two screws
c. Plug the wires back in
6) Replace the sensor
a. Carefully put back where you took it out
7) Test the system.
a. Start the car
b. Calibrate the HVAC, AUTO/OFF, there should be no 8 or other codes.
c. You may have to do this a few times, the old yellow shaft should drop out.
8) Replace the under dash cover
Outcome:
This was done on a 99 9-5 sedan. There are a few other issues that may cause this problem. The stepper motor failing (rare), or the stepper motor gear coming loose. Most of my time was wasted trying to get the old shaft out the realizing that it does not come out.
References:
http://www.eeuroparts.com/images/12765865%20Blend%20Door%20Repair%20Instructions.pdf
http://www.thesaabsite.com/95/saab%2095%20heater%20box%20repair%20aluminum.htm