No air at dash vents, stuck on defrost and feet?

Tiny
JERMJACK3
  • MEMBER
  • 2002 CHEVROLET SILVERADO
  • 6.0L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
When I switch to have air at the dash vent, nothing comes out. It seems to be stuck on defrost and feet. The fan is working just fine along with the heat/AC. Just seems to be an issue with the Mode Actuator. However, I can see the actuator moving but to no avail.
Tuesday, September 13th, 2022 AT 9:46 AM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

If you are unable to change the airflow direction and you see the mode door actuator respond to a change, then either the mode door actuator cam has failed, or something has broken on the door itself.

What I suggest is this. Remove the actuator and inspect the cam and where everything connects. While it is removed, move the door to see if you can direct air from the vents.

Let me know what you find. Also, I attached two pics below to make sure we have the correct components. The info is for manual climate control. If you have automatic climate control, let me know.

Also, here is a link you may find interesting:

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Take care and let me know if you have questions.

Joe

See pics below.
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Tuesday, September 13th, 2022 AT 9:00 PM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
I haven't taken the actuator out yet but the white gear controlling the door, I believe, was not engaging with the actuator. The actuator was not moving far enough. I was able to assist it back in place, but it is a few teeth off and won't completely switch to defrost now. Vents have air just not defrost now that I moved it in place. I'm leaning more towards the actuator going bad and not fully rotating.
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Wednesday, September 14th, 2022 AT 2:43 PM
Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
From what I see is that the actuator is not working properly, you may need a new actuator.
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Wednesday, September 14th, 2022 AT 4:34 PM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
I'm planning on replacing it. Thanks for the help.
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Wednesday, September 14th, 2022 AT 5:27 PM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
Do you have any tips on making sure I line up the new one correctly?
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Wednesday, September 14th, 2022 AT 5:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

By any chance, do you hear a clicking sound from the actuator? There are plastic gears in it that fail and then the actuator can't properly operate.

As far as tips for replacement, I attached the directions below specific to this vehicle. I selected a system without RPO D07, which is a center console. If you do have one, let me know.

Let me know if this helps. I highlighted the area that I believe will be of most interest for you.

Take care,

Joe

See pics below.
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Wednesday, September 14th, 2022 AT 6:41 PM
Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
It is not hard to replace just take your time lining. You showed me the video of the of the actuator working part way. There are two screws holding it in place. From the video you look like you can get at it easily enough.
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Thursday, September 15th, 2022 AT 7:35 AM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
This is becoming a nightmare. When I get the defrost round pin lined up and then the white gear, which took forever, install the screws no it won't turn at all. I remove it, plug it in and it turns just fine. This is a new actuator. If I move the white gear the defrost round pin falls. You can hear the doors letting go. What I need is to know exactly how to have the white pins and gear oriented along with the actuator.
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Friday, September 16th, 2022 AT 2:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

I noticed that it has been a few days since you were contacted. By chance, have you been able to get things aligned? If not, here is what you need to do.

You have to install the mode actuator as an assembly with the actuator cam. First, line up the heater/defroster valve lever with the mode actuator cam slot. Then, line up the A/C valve lever with the mode actuator cam.

At that point, you can install the mode actuator mounting screw to the HVAC module.

Let me know if that helps.

Joe
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Monday, September 19th, 2022 AT 6:27 PM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
I was able to get it in but it's still not working right. I'm taking it into a shop now. Thanks for the help though.
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Monday, September 19th, 2022 AT 6:59 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

I'm sorry to hear that. What is it doing now? Were you able to get things properly aligned?

If you take it to the shop, is it possible for you to let me know what they find? I'm interested in knowing.

Let me know.

Joe
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Monday, September 19th, 2022 AT 7:22 PM
Tiny
JERMJACK3
  • MEMBER
  • 7 POSTS
I thought I got it aligned but now I don't get any air to the feet.
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Monday, September 19th, 2022 AT 8:14 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Are you installing the actuator as a unit with the linkage?

Joe
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Tuesday, September 20th, 2022 AT 5:57 PM

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