Howdy all. I've run into this weird issue where if my truck is in the garage or already cold the AC seems to work just fine. If it sits in the sun during the day the AC fails. It still blows air, but never gets cold, no matter how long I drive or cold it gets outside. Had the freon topped off. Still same issue. Any ideas what could be causing this?? The shop is clueless. Thanks for the help.