I now have beautiful cool air wafting regularly out of my 560SEL center vents, and it's oh-so-nice. I recall someone on the board mentioning that the diaphragms have to be seated perfectly within the rim of the pod in order to function correctly. So when I removed the acc panel and pointed the flashlight to the back of the pod which had been replaced in 2010 with all the others by a previous owner, low and behold, it appeared as if the pod was assembled incorrectly and one section of the diaphragm was pinched within the seam between the back and the cup, allowing intermittent functioning at best. It was too difficult to seat the diaphragm correctly with the pod in place since I couldn't see all the way around it, so out it came. When I put the pod back together at the bench, it held pressure perfectly. But, by then it was too late. Might as well use the brand new one. Tips and tricks; I would (probably) not have been able to do this job without a very long pair of curved surgical hemostats to separate and then later join the arm to the white barrel clip on the vent door. I also used a long & thin "stabby" tool used in book binding to get in there and rotate the barrel clip to just the right position to then squeeze the end of the pod arm into the clip. Also, I purchased a long 5.5mm socket along with a 1/4" u-joint swivel piece to get at the small socket screws holding the base of the pod in place. When I put the screws back in, I placed a very small piece of paper towel on top of the screw head, then jam it into the end of the socket so the socket screw does not fall off of the socket when trying to get it back there in the correct spots. All in all, I was really really dreading this job based on what I've researched on this forum and the confining space under the dash, and there were definitely some frustrating moments along the way with trying to get that arm correctly lined up with the clip through that tiny hole in the hvac box, but it wasn't all that bad and it didn't take as long as I thought it would. It's supposed to hit 105 degrees here in Phoenix by Sunday, so I am definitely grateful this job is over.