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Recently when starting the truck, a ticking/knocking noise is coming from the passenger side dash around the glove box. it will last for 25-50 seconds and then stop. When shutting the truck off the ticking/knocking noise from same area will last for sometimes a minute, truck is off. I made a video of the noise thinking I could attach it, no luck. Anybody experience this or have an idea what it could be? Truck runs great, no warning lights come on.

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Recently when starting the truck, a ticking/knocking noise is coming from the passenger side dash around the glove box. it will last for 25-50 seconds and then stop. When shutting the truck off the ticking/knocking noise from same area will last for sometimes a minute, truck is off. I made a video of the noise thinking I could attach it, no luck. Anybody experience this or have an idea what it could be? Truck runs great, no warning lights come on.

Thanks
Upload the video to Youtube and copy the video link from the address bar, then paste the video link here in the forum
(y)
 

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When you figure it out, please make sure to post it up here. My 92 has done the same thing since I bought it 3-4 years ago. I have been too lazy to tear into the dash to find it. I’ve gotten so used to it that I hardly notice it anymore.
 

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That will most likely be the recirculation door actuator. There are 3 door actuators controlled by the HVAC controller. 2 of them have position feedback and go to the commanded position and stop due to feedback from the rheostat in those actuators to the HVAC control panel. The recirc. door actuator has no feedback and is commanded to full open or full close and power is applied to it from a time delay to give it enough time to drive full travel. After the plastic gears get old and brittle, a tooth will break off and the motor will run the actuator against that broken tooth gap and cause the popping noise until the time delay times out. In my opinion, it's impossible to replace the recirc. door actuator without pulling the dash out. Once you see the location, you'll understand.
 

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Thanks for the help!
 

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That will most likely be the recirculation door actuator. There are 3 door actuators controlled by the HVAC controller. 2 of them have position feedback and go to the commanded position and stop due to feedback from the rheostat in those actuators to the HVAC control panel. The recirc. door actuator has no feedback and is commanded to full open or full close and power is applied to it from a time delay to give it enough time to drive full travel. After the plastic gears get old and brittle, a tooth will break off and the motor will run the actuator against that broken tooth gap and cause the popping noise until the time delay times out. In my opinion, it's impossible to replace the recirc. door actuator without pulling the dash out. Once you see the location, you'll understand.
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That is absolutely a recirc. door actuator with a broken tooth.
 
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