My wife just got back into town driving our 2006 Cummins (ya, she looks good in it). She said the A/C was making a noise. When I checked it out and turned the fan on to the second highest position and the highest position the whole cab vibrates and sounds like and airplane is taking off. I looked in my Haynes manual and the only thing I can find is the fan clutch. Any suggestions? Also, does it need to be fixed before I tow our camper this weekend? Thanks in advance.

 

It sounds like you picked up a leaf or something into the evaporator housing and it is getting into the electric fan that pushes the air through the system. If the A/C/ fan is making the whole cab vibrate, you may have a broken blade(s) or something stuck in the fan.

The fan clutch should be under the hood between the engine and the radiator. Running the A/C should not affect the fan clutch directly based on A/C fan speed. If you have electric fans on the truck and they are attached to the A/C then they should either be on or off based on the A/C compressor being on or off.

 

Crank the fan wide open for a min and see if it goes away

 

agree sounds like cabin air blower fan

 

awesome, thanks guys. I will check it out.

 

hey man posted a little while ago and then went to phisical therapy and when I came out and started home mine is now doing the same thing going to take it to dealer tomarrow and will let you know what is wrong with mine. 25,000 miles this sucks

 

UPDATE - I went and got a new blower fan and pulled the old one out. In the process a little plastic piece was sitting in the basket of the fan. I pulled the plastic piece out and reinstalled the original blower fan and it worked flawlessly. So I pulled it down again to figure out where the piece of plastic came from. Straight above blower fan housing was a plastic panel that is roughly 4" x 7" with a foam strip around the perimeter that was just sitting there loose over the hole. I was above to drop it down and remove it. It looks like maybe it is some sort of trap door that allows when the air from the outside is brought into the cabin and when it is closed it recirculates the air within the cabin. Well the plastic piece that I found is from the hinged side of the panel. How it ever broke off is way beyond me. Now I need to see how I can get another panel and how it needs to be locked back in. My guess is I need to take the top panel off of the dash. Any suggestions?

 

That sounds like the blend door. That is a common problem on our trucks, it gets quite a few guys. My neighbor had his break a few months ago and he only has 15k on his 06.

 

You are exactly right. I went to the dealership today and they said it is a very common problem. In fact, they gave me a brand new housing to replace the existing that should not allow the problem to happen again.

 

Since this appears to be fixed, I'm closing the thread. It can be reopened if needed.