Got an A/C problem. System is 100% pumped up. Problem is that most of air is coming out the front defrost and little of it is coming out of the vents. When the humidity is high, have to keep the wipers on.
Took it to my mechanic and he tells me it is the "vent doors" and he would have to take the dash out. 20 hours labor. I think some tube is loose inside, because it seems the really cold air is hitting the windshield. Sometimes no air comes out the vents and 100% goes out defrost. I hear gurgling and then it starts coming out the vents.
I can cut it off and turn it back on and it starts coming out the front vents. But it does not stop blowing out of the defrost.
Any suggestions?

 

Vacuum pump would come to my mind first if you have not got this fixed

 

The most common problem when air is coming out of the defrost vents and you you don't have it selected is a vacuum leak. Most commonly the leak is on one of the vacuum lines going to the hubs. You should check the vacuum lines coming from the hubs to the vacuum pump follow the lines up to the pump and you will most likely find a section of line rotted and cracked. You could also cap off the line that supplies vacuum to the hubs and see if it restores proper function to the hvac. You can cap it with your finger if you have some one it the truck to tell you where the air is coming out.

 

The Heat/AC system is powered by vacuum. If there is insufficient vacuum to power the system, it defaults to blow out the defrost vents.

Fix the lack of vacuum/vacuum leak and you will fix the AC problem.