My wife's Traverse was not providing great AC last week. I hooked up the gauges and the pressures were within spec; hence the problem was elsewhere. I suspected an actuator since with the AC running full on the vent air was not cold. The vents were switching position so that ruled out the blend door actuator, but after removing the lower kick-panel, I noticed that the hot/cold air intake door actuator was only functioning sporadically.
The fix for these things is straightforward. Remove the glove box, box fascia, under dash kick panel, and side transmission tunnel panel. All these panels are held in place by simple clips. With the transmission tunnel side panel out of the way you can get a good view up into the in dash HVAC unit.
The problem is removing the three T20 screws that hold the actuator in place. The bottom screw can be easily reached with a small bit driver such as this...
But the other two on the side and on top required a different approach. After several tries with tool combinations of varying success, I came up with this arrangement; a 1/4" drive handle with a 4" fixed extension coupled to a 4" flex extension and a T20 bit driver on the front -- all nicely taped so that they can't get lost in that underdash maze.
This allowed access through the a small glove box side opening and proved flexible enough to clear several obstruction to finally gain access to screws. Tough fiddly work, but they came out without a hitch.
Hope this tool combo helps someone else attempting this job. It's not hard, just time consuming and often frustrating working in such a cramped space.
BTW -- keeping the doors open for two hours plus will keep the accessory/courtesy lights on and drain the battery (not to mention overheating the fixtures). The fix is to pull the courtesy light fuse from the interior fuse panel; accessible on the far right hand corner of the dash -- right underneath the glove box. Pull down the flap and pull the 15A courtesy light fuse (2nd fuse in from the start of the middle row) with pair of small needle nose pliers.