My a/c blows cold enough to make you're ears hurt, but when driven down the road sometimes the a/c will switch from blowin in you're face to blowin through the defrost. When that happens you can let off the gas just a little and it will go back to blowin in you're face. I think the vacumn control valve has a vacumn leak but I don't honestly have any a/c experience at all. Any ideas of similar problems you guys have you can share?

 

i have a similar problem, when i put my AC on max, it will quit blowing altogether, put it on norm and its fine. it has to be some sort of vacuum thing, but norm AC is plenty cold, so i havent worried about it.

 

You have got a vacume leak somewhere. I would start by looking under the hood over by your blower motor. There sould be a white (I think-not sure what year your truck is) vacume line over near there. Make sure it is in good shape. For some reason that line has a tendancy of getting rotten ad breaking apart.
If that isnt it I would look behind the glove box next and then behind the heater controls.
Good Luck

 

Thanks for the suggestions, I'll start lookin this evening when I get home from work.

 

Was reading back thru some of the old posts and saw this- I had the exact same thing happen to me- it was the white vacumn line under the hood going to thte AC-it was dry rotted-I had to use a piece of small vacumn line to make it work right-I also replaced the vacumn holding tank but that may have not been necessary

 

Same little white turd of a vacuum hose cracked and disintegrated on me too. I replaced it with rubber vacuum hose, works fine now. Just treat it gingerly, if you look at it wrong it will break.

 

I wonder what is is about that white hose that makes it crap out before all the others?

 

Well I'm ashamed to say I have not yet looked for the leak, been fryin bigger fish, new baby (no more money), blah blah. I am gonna do it soon though, the hotter it gets the more priority fixin the leak will become. I'll let ya know if it was the white line when I get it:o

 

It seems it was an engineering screw up, poor choice of material. Doesn't seem to hold up with heat and age.

Seems kinda stupid to miss something like that, but I'm an engineer and I have missed "easy" things before, makes you feel like an idiot after you finish the job and find it later.

Poop happens!

 

Mine does the same thing going up a st teep hill and then goes back when the hill is crested