A/C Issues Under Load

[iceman2824]

I have a 2008 ford explorer, and i have a problem with a/c. Under loads or going up hills, also driving on the roads between regular speed limits, the a/c switches between vent to defrost. What can i do about this?.....any ideas?

 

[Davidm53]

Vacuum leak can cause those symptoms. You might check for any cracked lines.