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Discussion Starter #1
On my '04 Outback, when I push the defrost button, there is a loud rhythmic clicking noise from under the dash. I think it has something to do with a blending door servo that is near the gas pedal, but I have no clue what to do about it. Bad servo? Loose wire/plug? All other heat and air settings are working and no noises. Just the defrost. Kinda stumped.
 

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2001 VDC/SC One of a Kind
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The Auto AC controls have a self diagnostic mode.

With the ignition off, hold "Auto" and "Fresh/Recirc" buttons and start the engine. Turn the temp knob clockwise one click. Each character should lite up. Turn another click and if any number other than 20 shows, write it down. If just 20, turn another click and if no problem 30 will show. Turn clockwise again, and this one checks the door actuators, fan motor and compressor clutch, and push "Def" to toggle through the modes. Each mode definition should lite up with each push, 41 through 48 - 48 is the def door and when 48 is lit, the def door should move. Turn the knob again and toggle "Def" to see readings from each temp sensor.

Usually, when you get a clicking when a door actuator is trying to move a door, it is either something is restricting movement of the door or the actuator itself is worn and the gears are "skipping".

Attached is a locator for AC electrical components.
 

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Discussion Starter #4
Thanks, I will run the diagnostic. The servo seems to
want to keep going, like there is a limit switch that
is not working. I will see what the test shows and
reply. Thanks.
 

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Discussion Starter #5
I finally had time to try the diagnostic and this is what I got.....
On the first clockwise click I got a 25.
Second click I got a 32 and a 35. In this mode the
blending servo would cycle back and forth, in one
direction quiet, in the other clicking like it is not able to stop or something is jammed. Looking at the arm on the actuator (mode door actuator)?, seems like it is close to or at the end of its proper travel. I tried to help the arm go further with no change. When the servo is clicking it jumps a little with the clicking noise.
Does not look too hard to remove it.
 

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'99 Outback 2.5 GT auto & '97 LegOB w/ grossly insulted 2.5
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Defrost servo 'clicking'

Far as I know, there is a feedback potentiometer in each of the servos. Back when I was a line repairman, I'd get my hand on the recalcitrant servo & 'help it' to the end of its travel, allowing the logic stuff to 'learn' where end of travel was supposed to be. After I retired, I found a few with troubles related to a kid displaying his G/F's necklace from the car's mirror...until it took a dive into the defroster duct.
 

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2001 VDC/SC One of a Kind
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Thanks, I will run the diagnostic. The servo seems to
want to keep going, like there is a limit switch that
is not working. I will see what the test shows and
reply. Thanks.
The motor will continue he to run until it meats a point of resistance or the positioning sensor within tells it to stop.

You need the door actuator.
 

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2005 Outback LL Bean 3.0
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Sorry to revive this old thread. I was wondering if the diagnostic test described in an above post applies to gen 3 ob's. Or is there a different procedure?
 

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On the Super Mod Squad
2002 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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Sorry to revive this old thread. I was wondering if the diagnostic test described in an above post applies to gen 3 ob's. Or is there a different procedure?
find another thread in the gen3 section.

different ones for plain old, and dual automatic climate control. (lots and lots of threads there)
 
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