Odd noise from under my upper dash

2011 King Ranch EL. A week or more ago, a random noise has been coming out from what seems to be my upper dashboard. At first, I thought it was a speaker popping, but realized there's no speaker there. The noise generally happens right after startup and lasts for maybe 10 seconds, although it happens randomly at times also. It sounds like the speaker pop that would happen when you turn on a radio if the amplifier does not have a "soft start" function. It pops at roughly 3 pops per second for around 10 seconds max, then goes silent. I have turned off both my sound equipment, and my climate control system as I thought it might be a bug in a blend door controller. Anyone have any ideas? It's kind of irritating.

It's the blend door gear that has broken a tooth.

Not an easy tear down but it's on YouTube how to do it. With mine, I just have to keep the temp setting 2 notches off of full cool and it doesn't happen for me but it depends on what tooth is broken.

Definitely sounds like a blend door actuator. As to the difficulty of repair, it depends on which actuator is bad. I've replaced two of them on my 2011 Limited EL - one behind the stereo and one under the dash behind the steering wheel and next to the brake pedal. The one behind the stereo is pretty easy to replace, but it doesn't sound like that's the one you're having an issue with.

My guess is it's the one next to the brake pedal. Here's a link to the notes I wrote up on how to swap it out including the tools needed. Not the most difficult job in the world. I wish I would've had more hints on what to expect and what tools to use, but that's ok.

I appreciate the responses. As to which actuator, I have no idea. I am guessing the one behind the radio as the sound seems to be high in the dash, near the defrost port. I am curious as to why it would sound even with the climate controls completely off. Possibly it's a normal "post start" check of some kind? It never sounds more than maybe 10 seconds and then quits for a very long while.

Yes. It starts off checking the position.

One way to figure out which one to go after is to turn on the cool/ heated air. Make sure you get both. Then change modes… floor, dash, and defrost. Make sure air flows from those positions. If you fail to get heat it’s the blend door actuator. If the airflow fails to follow switch positions it the mode door actuator.

With that part figured out you will have to locate the position of these actuators, and swap it out.

So, here’s a little tip to save you some heartache… before installing the new actuator make sure to position the motor male stem in the current position of the door female mount. Example… if the current position blows cold air (though the dash is set to heat) the motor will be working against the door. It’ll break itself. You must adjust the temp setting so the motor actuates the motor make stem to a position that will allow it to mount the female end properly aligned while allowing mounting hardware to align as well.

Hope I didn’t confuse you. Can someone maybe clean up the explanation for me. Thank you.

Thank you Ellison Brown III. That information helps a lot. I may already have the answer. The weather here has been colder over the last week or so. I turned up my heat a bit to compensate. I have not heard the noise since that change. So apparently it's the blend door actuator is popping when I have it adjusted to the cooler side.

purevw said:

I appreciate the responses. As to which actuator, I have no idea. I am guessing the one behind the radio as the sound seems to be high in the dash, near the defrost port. I am curious as to why it would sound even with the climate controls completely off. Possibly it's a normal "post start" check of some kind? It never sounds more than maybe 10 seconds and then quits for a very long while.

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I could be wrong, but it sounds like it's the defrost blend door actuator. It's a easy one to check as well because it's under the dash next to the brake peddle. You can put your hand on it to see if that's the bad one. The other require a lot more work to physically touch. Good luck with your repair.