First off I'm new to the form so bear with me if I don't get it just right. I have a 2001 Gen 2 2500 V10 issue with my AC is not blowing out the vents all the time it works sometimes but not all the time sometimes it'll just blow out on defrost sometimes I can get it to blow regular but then when I shut the engine off and start it up again it will just blow out defrost a friend of mine told me that it might be the mode actuator but I can find nothing online that says it has one so my question my first question is does it have a mode actuator second question is if it does not what else can I check I've heard vacuum leaks are possible but other than that I am stumped any help would be much appreciated

 

All the vents are vacuum controlled. The temp door is driven by an actuator, but, that ain't your problem. If there is insufficient vacuum, the vents default to defrost. A vacuum leak somewhere is likely.

 

I will give that a try I will look for a vacuum leak would that cause it to work sometimes but not all the time?

 

Yep.

There is a TSB about the problem as well. Should find it in the FAQ/DIY section under something like 'wild vents'.