Where is the Mode door actuator located?

Tiny
ELIANBUCHI
  • MEMBER
  • 2010 CHEVROLET MALIBU
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
I am trying to locate the mode door actuator. The air in my car is only blowing from the defrost vent and the lower vents and not blowing from the dash vents. I suspect that there is a problem in the mode door actuator. A couple days ago it started blowing from the dash vents but a couple days later the problem happened again. I would appreciate any help. Thanks
Thursday, May 30th, 2024 AT 2:45 PM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
The mode door is located on the top left side of the HVAC case. From your description it doesn't sound like the actuator itself, but controller related. I would try a hard reset by removing the HVAC ctrl fuse from the body control module. To get to it you remove the right-hand console trim panel and the BCM is behind it. Remove the fuse, keep it out for about a minute. Now put it back in and let the system reinitialize. Test it, do the vents now work? If yes, then it is likely the control head and not the actuator. This could also ne tested using an OE level scan tool to move the actuator.
To get to the actuator itself you can try reaching way up to get to it but the way GM wants you to get to it is to pull the dash out to get to the HVAC box and change it that way. That entails recovering the AC system, draining the coolant, removing the console, disconnecting the steering column and unbolting the dash. Then you remove the HVAC unit from the back of the instrument panel to get to the actuator. This is another of GMs fun vehicles where the part is like $35 but it's 5 plus hours of labor to get it replaced. There might be a shortcut posted online at a place like https://www.chevymalibuforum.com/ or possibly YouTube I usually go by the book and while it's out inspect the heat and AC cores as well as the door seals and other actuators while it is apart.
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Friday, May 31st, 2024 AT 4:23 AM
Tiny
ELIANBUCHI
  • MEMBER
  • 3 POSTS
Hi Steve W. Thank you so much for the information. I removed the fuse that you indicated and allowed a minute to pass before putting the fuse back in and turning the car on, however, that did not resolve the issue. Yesterday (before reading your post) I pulled part of the dash out and I was able to see the mode door actuator and was able to observe it moving when changing the vent settings from defrost vents, front vents, and floor vents. The actuator would move when you select any vent setting except for the front vents. I then manually moved the door (the piece that is attached to the actuator) to the bottom, and then air was coming out of the front vents. I then changed the knob, so air goes to the floor, and it did, then changed it to defrost and it did change. I repeated the process a couple of times trying different settings to see if the actuator would move when the setting was on the front vents. The actuator moved to the front vents a couple of times then it did not anymore, but it continues to move to the other vents when prompted, I had to manually move it in order for it to move to the front vents. I am not sure if there is something that is making the door get stuck when it tries to move to the bottom (allowing air to come from the front vents) or if there is an electrical or other mechanical issue.

In your previous response, you mentioned that the control head might be the problem, would you mind telling me what the control head is, where to find it, and if you still suspect it as the problem?

If the problem is with the actuator itself and I am able to pull it out without removing all of the other parts, would it be advisable to do so or is draining the coolant and removing the console necessary parts of the process?

I was also trying to find the actuator at AutoZone or Advanced Auto but for some reason, no one has this part, do I need to buy it directly from GM, and if you happen to have the part number, I would appreciate it too.
Thank you again so much for your time and expertise.
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Friday, May 31st, 2024 AT 6:53 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
If you can see and access the screws that remove it, then great. It sounds like the actual door is sticking, not the actuator. That would require pulling the entire dash out so you could access the door inside and see why it is binding. If you can move the linkage so the door changes try this, select the floor vents, now select the dash and gently assist the actuator as it moves, does it feel like it's binding or is it still moving some after the actuator stops? Can you get to the electrical connector and unplug it? The way that system works is that the control head tells the actuator to move and then it looks for a certain value on the potentiometer to tell it when the door is in position. If the door is free, then it could be the return signal that is bad. Hard to tell without physical examination. The part is very likely GM only at this time, but in looking at the various GM parts sites it only shows the complete assembly. I would see if you can read the part number on the actuator and use that. Is the image attached what you are looking at?
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Friday, May 31st, 2024 AT 7:41 AM
Tiny
ELIANBUCHI
  • MEMBER
  • 3 POSTS
I was able to take the actuator out and the plastic part that sits on the actuator. The plastic piece has groves in it in which there are three white pins that sit in the groove and move as the actuator and plastic part move. These pins move along the groves and control where the air is coming from. When I took the actuator out (it took a couple of hours without pulling the entire dash out) I cleaned the grooves as there was crusted grease which I believe was causing the binding and I added more grease into the grooves to help the pins move freely. I put the actuator back (which took a lot of time and I needed the help of another person, I had to take the radio out, so the other person is able to place the pins in the correct place while making sure the screw holes were in the correct place). Now everything is working perfectly. Just for reference and if anyone is wondering how to do it without pulling the dash, the way I was positioned was very awkward. I had to put the driver's seat all the way back, my feet were on top of the seat where the head is usually there, my head was near the brake pedal, and I was inverted on my back. If anyone knows of another way to do this job, I would very appreciate it.
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Friday, May 31st, 2024 AT 7:03 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
Great to hear you got it done without tearing the entire car apart. I have done a couple other brands that way. Always fun.
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Friday, May 31st, 2024 AT 7:31 PM

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