Sometimes when I turn my AC on I hear a loud thunking coming from the rear cargo panel in the trunk area of the navigator. It is like a piece of plastic catching and then flexing forward. It only occurs when I turn the AC on. Is there a vent or common issue with the way the ac routes through that area that is causing this noise? Its loud and occurs every few seconds the ac is running. I believe it is coming from the passenger side.
Country: United StatesMake: LincolnModel: Navigator L UltimateYear: 2003
Hi, I’m Chris. Welcome and thanks for asking your question!
If you slowly adjust the rear air temp does the noise stop occurring in one temp setting?
I'm not sure about that. I'll try it next time I hear the noise. It's intermittent is what drives me nuts.
Thanks for the reply.
Next time this occurs if the test I mentioned above stops the noise then the concern you have is broken blend door shaft or a blend door actuator that controls the blend door on the rear HVAC unit. See the image below and let me know at that time if you plan to address this yourself, and I will assist.
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Hi Chris. I finally have the time and money to address this. I tested changing the temp and speed for the fan in the rear. What I found is that the thumping is much louder when the temp is set to Cool, goes away as I start to adjust it towards the center, and can still be heard lightly if I go all the way to hot.
Did you use the information in the previous post to get to the HVAC blend door actuator to see if the actuator or door is faulty. Do you need assistance accessing it if you plan to do this repair yourself?