First post, go easy on me! Just bought an 04 F150 lariat, 5.4L with 52k miles. The AC isn't very cold but the back seat vents are coldest, passenger front is cool, and drivers vents blow barely cooler air than ambient. When I switch it to defrost, I get a brief second of actual cold air from all vents. System seems to change zones appropriately and heat works great. I don't hear the grinding noise some speak of and the doors seem to operate smoothly with no extra noise. First thought was low freon so I did a quick check with a can of AC pro and gave it a shot and its within range. I don't believe this to be the issue anyway because I do get the cold air like I said in some vents and when placing it into defrost. I did search for an answer but just couldn't find exact problem. Thanks and thanks for the add.

 

Either a blend door issue, or an issue with incorrect charge

Checking with a tiny gauge on a can is not an accurate measurement of how much or how little is actually in the system. It's just going to give you an approximate measurement of low side pressure.


As for possible blend door issue, do you have dual climate control or is it single front temp?

 

Single climate