Plastic Jackhammer Noise!?

[Aeterna]

I have an 07 tahoe that once in a blue moon something in the dash area (i think) sounds like a plastic jackhammer and wont go away until I turn the car off and back on. From memory, this seems to only happen when I first start the car. But maybe it has happened randomly when driving too.

I believe this is a blend door issue, but can anyone tell me if there is one blend door that is more problematic that I should replace first? Reason I ask is because this issue is so random its hard to figure out which one is the problem.

I have tried cycling through different types of airflow which doesn’t cause the problem.

 

[Fless]

An advanced scan tool can test the actuators and tell you if they're positioning correctly. Maybe try to find someone with a Tech 2 or another capable scanner.

In what part of the country are you, if you don't mind me asking? Someone on here with a Tech 2 might be close by.

 

[Aeterna]

An advanced scan tool can test the actuators and tell you if they're positioning correctly. Maybe try to find someone with a Tech 2 or another capable scanner.

In what part of the country are you, if you don't mind me asking? Someone on here with a Tech 2 might be close by.

oh nice that sounds like a solid option, think a reputable mechanic would have a Tech2 is that a standard piece of equipment?

I am in central Texas. So hypothetically, if the actuators pass, is there something else this noise could come from?