Hey All,
Have an '07 FX4 that started to make some funny noise this winter.
It sounds like super faint far off machine gun noise. Almost like the beginning of Metalica's "One" song. It is a random and faint clicking noise. I only hear it on the low fan setting. It sounds like it is directly behind the speedo/tack guages.
All fan speeds and temps are working well.
Any thoughts?
Thanks.

 

There is an actuator that opens and closes the blend door. This is mounted on the top side of the evaporator/heater core housing. This part is notorious for crapping out and you HAVE to remove the dash to get to it. I don't think the part is expensive, its the labor that will get you. If it gets louder like a popping grinding noise then it is time to replace the part. You will know if it stops working because your climate control will cease to work leaving you stuck on hot/cold or a mix of both. That's my best educated guess based on personal experience. They can be noisy for a long time before they give up the ghost.

 

agree to malexander52, had this issue is 03 expedition and my 08 f150 is haveing it right now, very faint and random like a pulsating sound. I find that if i hit the button for floor air then change to upper vent and back makes it go away for a day or so.

 

Started acting up on my '08 as well this winter, light tapping sound when temp control is set on medium (between 12 and 2 o'clock on the manual dial - low fan). It will disappear if I set temp lower or higher, and cannot notice on any other fan speed but low. I've done a bit of research online, and some say it is the blend door actuator which can be gotten to by removing the radio and glove box (not entire dash), and hoping this is the case.

 

I had/have this same problem with my 2008 FX4 with automatic climate control. Just before my warranty expired they replaced the blend door actuator, it was making the hard drive, pumping, sort of sound. The mechanics at first couldnt verify, then once mechanic said he had heard of the problem. He said that he had to remove the heater core to get to it and disassemble the entire dash. At the time, the nosie seemed to come from the glove box area, maybe close to the radio. This time it is different, it seems to be coming from behind the dash instrument cluster. Anyone know if there are two actuators? Hopefully this can be reached without total disassembly? Am also hoping it can be reached by removing radio. Any input is appreciated.
Thanks

 

Definitely coming from behind the instruments for me. Nothing changes as I adjust the temp only the vent locations. I usually drive around w/the lower vent on and that is when I hear it on low. Maybe the fan drowns out the sound on higher fan settings.
I can hear the "selector" making noise as I change the active vent locations.
It is definitely not coming from the glove box area.

 

I have same symptoms, not too much problem with temperature regulation, but more of an irritating noise issue behind instrument cluster; any "how to" on replacing and location of blend door for the driver side?