Mode door actuator replacement?

Tiny
VOODOOBOOM
  • MEMBER
  • 2005 GMC YUKON
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 165,000 MILES
I have an auto HVAC system. My mode door actuator does not seem to be working (no matter what position the digital display indicates, defrost, vent, floor vent, defrost floor, floor the air flow does not change). It comes out on defrost and floor at the same time. When I look under the dash at the mode door actuator while pressing the position button, the actuator does not move or do anything. My question is when replacing, how do you align it (where should the white gear be?)? And how do you calibrate it to ensure there is no damage done?
Sunday, July 22nd, 2018 AT 7:04 PM

3 Replies

Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello, I am Danny.

I have attached a picture but I do believe you know already where it is located based on your post. I have also attached a how to link. When replacing the mode actuator as an assembly with the actuator cam, line up the heater/defroster lever with the mode actuator cam slot. Next, line up the A/C lever with the mode actuator cam. Hope this helps and feel free to ask any more questions if needed. Thanks for using 2CarPros.
Danny-

https://www.2carpros.com/articles/replace-blend-door-motor

Check out the images (Below). Please let us know what happens.
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Monday, July 23rd, 2018 AT 12:07 AM
Tiny
VOODOOBOOM
  • MEMBER
  • 2 POSTS
Hello Danny,

Thank you for the quick reply. Unfortunately, The instructions you provided are actually the basis as to why I asked my original question. Those instructions are for the installation of a Blend Door Actuator. I have replaced (and re-calibrated) those before. Although I understand that the "concept" is the same with both actuators, the mode door actuator seems to be a completely different animal. I have done pretty exhaustive research and from everything that I read about the mode door, it is a complete nightmare to line up.

You say "line up the heater/defroster lever with the mode actuator cam slot. Next, line up the A/C lever with the mode actuator cam" This is confusing to me. I have an electronic push button auto HVAC control system. So what is my starting point? How do I know what position to start from (post coming through actuator, white gear)? Do I leave that alone? Do I unhook the battery, Install and then re-calibrate the same as the blend door actuator? How do you align that with the gear on the mode door actuator assembly? Are there marks? What is the A/C lever? When you look up there, there is the actuator and cam assembly and what looks like "guides" underneath. Right above it there is a white gear with teeth that seems to need align some how with the teeth on the mode actuator assembly teeth, but it what position? I assume that the mode door actuator comes centered (range of motion). But I assume that the rod coming out of the heater that actually changes the modes is over extended or not where it should be. How do I ensure that it is in the right position? From what I read if you put it in the wrong spot, you will ruin your actuator by it going past its intended range of motion. Does the system need to be re-calibrated in some way? I am actually really surprised that there are no specific instructions, how to video's or anything basically anywhere. Sorry for all the questions, but I cannot seem to find any easy to understand instructions. Thanks
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Monday, July 23rd, 2018 AT 8:15 AM
Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello again,

Here is what I found for the upper and lower mode door replacement. I've attached the step-by-step pictures below. Hope this helps and thanks again for using 2CarPros.
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Wednesday, November 13th, 2019 AT 5:28 PM

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