Problem: Fan never turned on resulted is Kinect overheating and power cycling.
I researched the problem on various threads and decided to take it apart and see if I could replace the fan, as already noted by others. Before ordering a new fan I wanted to check the existing fan independently and determine if it was at fault. Upon removing the fan and checking it with a 5V power supply, I was able to confirm that the fan worked correctly. When reinserting the fan into the connecter receptacle, the connector broke off of the PCB. I inspected the connector and PCB and did not find any damage on the connector or the pads on the PCB. I cleaned up the pads on the PCB with a little solder wick, replaced the connector and gave the pins a fresh coat of solder. Reassembled the unit and everything seems to be working fine.
Just seems to me to be a manufacturing issue where the solder screen machine did not apply enough solder paste prior to SMT resulting in connections that were cold/intermittent, failing over time.
I took some pictures but not sure how to add them to this post.