Product review (4 stars): How to make it colder if you have the alternate version
As most of you know this cooler does not make beverages cold enough to be enjoyable, and other reviewers have posted very helpful tips on how to adjust this cooler to make it usable.  However there is an alternate version of this cooler out now that has moved the thermostat adjustment screw.  If you pull the black control knob off the front and do NOT see the adjustment screw to the left that others have described, here is how to perform this same hack on this newer model.

(1) UNPLUG THE COOLER!
(2) If you haven't already, gently pull the black control knob off the front of the thermostat.
(3) Remove the three screws (Phillips) that mount the thermostat control box to the top of the cooler.  There are two in the front corners, the third is in the center of the back.
(4) With the thermostat control box hanging lose, carefully pull up the metal control housing in the center of the box.  You don't need to remove it completely, just enough to expose the small screw on the left side.
(5) Using a small-tipped Phillips screwdriver, turn this screw COUNTER-clockwise to make your unit colder.
(6) Reverse steps 1-4 to re-assemble.

It is very easy to accidentally turn your cooler into a freezer, so use a thermometer and check the temperature after several hours.  It's best to make small adjustments until you get it right.  If you can ensure that kids won't be getting into the cooler and getting shocked, I found it best to just leave the thermostat disassembled until I had the temperature correct.

Once you get it right, put everything back together and use the black knob to fine-tune.

It's a great cooler once you make this adjustment!