Hi, I have a questions to see if anyone has heard of this. My truck F250 2006 6.0 4x4, has been doing something weird. As I am driving with the A/C on coming through the front vents, I switch the truck into four wheel drive high. The A/C then stwitches vents and starts blowing out the vents by the windshield, and stops coming out the front vents. It lasts about 30 seconds then the A/C will switch back to normal, coming out the front vents. Not sure what to look at as far as troubleshooting. Any suggestions?

 

Vacuum leak on the lines going to the front hubs.

 

Check out the tech. section under ESOF. I think you might find your answer

 

The 6.0 Tech Folder? I searched that and didnt see ESOF, or is under Tech Guides?

 

Try the search bar on the top of this page, there has been a lot of posts about vaccume leak on the 4x4 trucks.

 

Here's a good one. Gets down to business on the second page.
https://www.ford-trucks.com/forums/8...n-defrost.html

 

Ok. Thanks for all the help. I will tackle it this weekend and update.

 

Good luck with it. Post back if you get stuck.