Yesterday my front passenger and i noticed a front knock eminating from the front passenger side dash. It seems almost totally random and it would do it from 5 to 30 seconds. It varies in loudness but is always noticable nd the ac was on. does anyone happen to know what this mayne?

 

Does it stop with the HVAC off? Does it change if you change temperatures on the HVAC? My guess would be blend door.

 

Its not as prevalent with the hvac off but every now and again it will with it off

 

Does it do that when you are stopping / starting or turning quickly? Could still be the door flopping around. What about if you change temp?

 

It happens with the truck on but it can be in park and not in motion with the hvac off or on

 

Well then that's not it.