I was curious what you used to do the smoke test? I've seen a bunch of youtube videos but I kinda liked this one over the cigar method or buiding my own
I had threatened to buy one of these fog machines in a post a month or 2 ago to do a smoke test but put it off. It's halloween season soon and the stores should be carrying them and I'll be able to decide better which to get and give it a try.

 

I think a fog machine would work perfect. I personally used a cigarette. Make the best out of a bad habit. However it seems to have done the trick! Ac is working in the front vents again.

 

That could be the an A/C compressor cutout relay. When stomping on the gas the vacuum drops, the contacts open and the compressor shuts down for more acceleration power.

 

.....

 

van with 5.2 L. and have same problem but mainly when ac is on max, it will blow through defrost vents. if i put it on reg ac, not max then it blows correctly but will still start blowing through defrost if I am accelerating then when I let off on gas it goes back right. also if I start it off on max ac and turn it to low it will blow correctly after about 10 seconds or so but as soon as I hit 35-40 mph it starts blowing through defrost again. have not solved this problem yet and now I am having a problem that when I turn on ac the battery gauge goes down and it blows the ac/starter fuse and will not start until I replace fuse. mine is a 98 ram 1500