Thats exactly what it is!
Originally Posted by Trouble
You have a vacuum leak in the heat/air system, it defaults to defrost under low or no vacuum.
i hear little plastic pieces in the duct work moving around when it happens! then kicks back to normal, so if i keep running it as is, will the problem get worst or will the A/C cut out all together?
Mr. Lopar, once i put the tail gate down, i tied a rope across the back hooks on the bottom to make sure it didnt fly up any higher. but once back on the road, the wind coming over the cab pushed the bedliner down and it no longer flys like that!