Rapid clicking when I start the truck?

Tiny
JACOB MARINO
  • MEMBER
  • 2003 GMC SIERRA
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 250,000 MILES
There is a rapid clicking noise coming from behind the glovebox area when I start my truck. It usually doesn't last longer than 10 seconds but had before. The truck starts fine but when I turn on the AC/heater, more clicking happens from around that area and it barely blows air out. Don't know if they're connected. I just replaced the wires for the blower motor not long ago.
Monday, October 9th, 2023 AT 1:06 PM

19 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Jacob,

What you described is a textbook description of a faulty HVAC door actuator. There is more than one, so I have questions.

You indicated little airflow. Does the temperature operation work properly? Also, are you able to change the airflow direction as requested? Let me know. Also, let me know if the vehicle has dual climate control and if one side or the other is affected.

Take a look through this link. It explains in general how a blend air door actuator is replaced. Take a look through the "What goes wrong" section in the beginning. You may find it of interest.

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

Let me know.

Joe
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Monday, October 9th, 2023 AT 3:29 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
I can change temperature okay hard to tell due to how much air comes out, but it feels okay. It is a dual climate system, and the driver side lets out a little air, the passenger side lets out no air it feels like. I can change the direction of the air fine. The video attached is changing the speed from about 70% to 100%.
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Monday, October 9th, 2023 AT 4:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Wow, I heard that. That noise isn't one of the actuators. It sounds like the fan is hitting something. If you get under the dash on the passenger side, place your hand of the blower motor and see if you feel a vibration when that sound is heard.

Let me know.

Joe
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Monday, October 9th, 2023 AT 5:00 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
Well, it's that noise when I run the AC/heater high, but the more rapid sound still happens when I start the truck sometimes.
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Monday, October 9th, 2023 AT 6:18 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
I put my hand barely on the motor to feel it and the sound got worse. Would that mean that the motor is bad or that I'd just need a new fan?
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Tuesday, October 10th, 2023 AT 12:42 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

If placing your hand on it lightly caused it to get worse, it sounds like it may be loose. Check to make sure everything is tight. If it is, then remove the blower motor and inspect it to make sure the fan is properly attached to the blower motor shaft.

I attached a pic below and highlighted the fan portion of the unit. Check that to make sure it is okay and check if it is rubbing something in the housing.

Let me know.

Joe

See pic below.
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Tuesday, October 10th, 2023 AT 7:17 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
It spins okay not the best. It has a little bit of wobble to it but I'm not sure how much room for error there is in the housing. When I lift or push on it though, it makes a sound similar to what it did. Would it just need tightened?
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Wednesday, October 11th, 2023 AT 2:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

The play shown in the video really isn't odd and at this point, isn't a concern. As far as the housing, is there any evidence that it was rubbing?

I do have another question. With that removed, is the sound gone?

Let me know.

Joe
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Wednesday, October 11th, 2023 AT 7:26 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
Yes, the sound is gone when I run the AC/ heater and I don't know if by chance, but the sound upon startup has been gone since yesterday.
Also, I can't get my head in far enough to see, but just feeling it, it doesn't feel scratched or rubbed on.

I haven't said it, but I appreciate the help here. This has had me stumped a while.
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Wednesday, October 11th, 2023 AT 7:46 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi Jacob, you are very welcome. That's why I'm here. As far as not being able to see, carefully hold the fan by the mount and turn it on. Be prepared for it to want to jump from your fingers. Spin it 360 degrees to see if the sound is coming from that portion of the unit.

There could be a bearing in the motor that is failing. However, since the sound is gone with it removed, I think we found where it comes from. We just need to determine what it is touching. If you have a small mirror, see if you can position it to see into where it mounts.

Let me know what you find.

Take care,

Joe
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Wednesday, October 11th, 2023 AT 9:36 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
It's a little bit hard to hear, but there is definitely a noise when it's at about a forty-five-degree angle. I did it once before the video I took, and it made that same noise from behind the glovebox we started about. I changed the temperature from 60 to 90 just to see if that's what caused it and I'm not sure if maybe it did?
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Thursday, October 12th, 2023 AT 3:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

I wish I could say with 100% certainty, but it is so difficult listening to a video. At times it sounds like there is a dry bearing which could be causing issues. Also, I did hear some variation in sound two times. Is that what you were referring to?

Also, the time you did it before recording, you indicated hearing the noise that was the same as the original from behind the glove box. Did the noise come from the motor or under the dash when you adjusted the temperature?

Let me know.

Joe
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Thursday, October 12th, 2023 AT 8:16 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
Yes, it was. Also, the sound came from almost dead center of the dash almost behind the climate control and it did it for a good 20 seconds I want to say. It didn't make the noise until after I shut off the AC.
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Thursday, October 12th, 2023 AT 8:26 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
I am leaning towards the actuators, like you mentioned. Since I have a dual climate control, would there be 2? If there is, would one cause the other not to work?
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Thursday, October 12th, 2023 AT 8:32 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

There are two. I attached two pics below showing the location on both sides. Since the noise came from the center, I suspect it could be related to the right-side actuator. Locate the actuator and see if it vibrates when you hear the noise.

Let me know.

Joe

See pics below.
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Thursday, October 12th, 2023 AT 8:57 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
It vibrates right here. It's on the left side behind the glovebox. I haven't had time to check really anywhere else yet but I will keep looking.
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Sunday, October 15th, 2023 AT 1:25 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If I had to guess, I would think it is one of the actuator motors. They have plastic gears in them that fail. See if you can narrow it down to which one.

Also, that is the area where both are located. One is higher than the other (right is higher). Let me know what you find. Note: If you can't tell the difference in the vibration, disconnect one at a time to see which one eliminates the noise.

Let me know.

Take care,

Joe
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Sunday, October 15th, 2023 AT 2:00 PM
Tiny
JACOB MARINO
  • MEMBER
  • 45 POSTS
Hey! Been a while, I apologize. I just got around to replacing the blower motor and the resistor and both noises seem to have stopped. Thank you for your dedicated help!
-Matt
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Tuesday, November 14th, 2023 AT 5:19 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Thanks for the update, Matt. I'm glad to hear you got it taken care of.

Take care and feel free to come back anytime in the future.

Joe
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Tuesday, November 14th, 2023 AT 8:32 PM

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