Weird Noise coming from my dash 2007 Silverado

[Andy]

I have a 2007 Silverado 1500 New Body Style with a V6. I have been hearing a weird noise coming from the dash area. I took it to the dealer and they could not hear it. It is not very loud. If I turn on the air or radio it drowns it out. Once I reach 5 miles an hour the road noise drowns it out. It has been going on for about a month and it does not seem to be getting worse. You can hear nothing from under the hood. I planning a trip soon and I want to make sure this is nothing serious. I have a video file that I will try to upload here and I plan on visiting the dealership tomorrow. I went to the dealer today and they did hear the noise this time. They looked it all over and could not find the source. They think it could be some part in the dash but could not confirm. At least it’s not getting worse. Turn the setting to one and you can’t here it. Went through all the gears at idle and the sound remains. I did try some things when I got back from there. I took my lawn blower and hit all the vents to see if anything might pop out. I didn’t help. So I have another bright idea to use my shop vac. Used both the suction side and the blower side. Did not help. So I guess it is what is. https://www.youtube.com/watch?v=RR8KByndYoA

Topic

[Andy]

Do you see the actuator? I think that is the resistor based on information received on this site. Dose anybody know where my actuator is and how many are there?

Thanks Andy

[Andrew Phillips]

There are three (or four if you have split temperature control left/right). I have attached a parts diagram. The actuators are parts #19 (air blend door), 20 (mode door), and 21 (temperature, x2 if split left/right controls). The one I suspect is #19.

Part numbers:
1. Evaporator core
2. Evaporator core Seal
3. Evaporator case Upper
4. Evaporator case Lower
5. Heat shield
6. Seal kit
7. Heater core
8. Heater case
9. Blower motor
10. Fan
11. Resistor
12. Blower case
13. Blower case Seal
14. Air Blend Door
15. Mode Door
16. Temperature Right
17. Temperature Left
18. Defroster Door
19. Actuator Air Blend
20. Actuator Mode
21. Actuator Temperature
22. Lever for Mode Door
23. Wiring Harness

Attachments:

• ChevrEvap.png

[Andy]

Is there anyway the resistor could could be causing this?

Attachments:

• 1B.jpg

[Andrew Phillips]

No. Plus, you said you unplugged it and the noise remained.

[Andy]

Your right. I forgot about that. I did have something different happen just now. I took a ride to the store and the A/C switched by itself to recirculate rather that the outside air default mode. I kept trying to hit the outside air option and it would flash and then go back. After I went to the store and got back in the truck everything returned to normal. Is there an actuator that controls this? And if it does where does it reside.

[Andrew Phillips]

Yes, it is part #19 on the diagram that I supplied, and has been what I felt all along was the issue.

[Author]

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