Hello all. I'm new to the forum - as well as a new-to-me Suburban owner. I've got a '99 5.7L (350) engine, 4wd, 143,000 miles. It's got the dual-zone climate control and all that jazz, but neither the front nor rear is working all that well. The A/C simply doesn't blow cold. More like barely cool. I'd call it warm. The rear *may* be a little cooler than the front, but neither is chilly by any stretch of the imagination. Starting with the basics, I checked the system pressure (with a gauge from an R134 recharge kit) and it read dead-on at 45, which is - according to my limited research - right where it should be. And now I'm about out of ideas, being that I don't know all that much about these systems. Looking for advice before heading to a mechanic. I'm a hands-on guy who will try to fix anything any way I can before paying someone else to do it, so teach me something! It's hot here in Arizona, and A/C is not an option - it's a necessity! Thanks for any/all ideas!