So i got the day off, i'm looking for a reason to take my rig for a ride, i decide to hit the coffee shop for a caffeine injection. It's raining, i put on the defrost ( so i thought ) blower to three, off i go. About two miles down the road on a snakelike curved road at about 30 mph i hear what sounds like a knocking noise.( bums me out immediately ) it does this for
about ten feet stops for about twenty feet then does it again for about another ten feet, i pull over, notice my windshield not de-fogging to notice i never put it on the defrost mode but rather i had it on the vent
mode with the vents closed. i turn it too de-frost mode continue down the road and cannot get the truck to reproduce the sound. At first i thought the sound was brake pad related or maybe i picked something up on the road that was bouncing around in my wheelwell,( passenger side front is where the sound seemed to be coming from ) now i'm wondering was my hvac system trying to tell me something like " yo
your asking me to send air through your vent system but you got the vents closed so the air has to go somewhere else " ..??????????? Any ideas anyone ?????

' 04 f-150 xlt 4x4
reg. cab flareside
drk toreador red

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