Where is the thermostat control on Westinghouse Jr?

[cormy]

Plugged it in and cooled the water down to 39 deg. in no time, but probably would have kept on going and I didn't want to press my luck. I see a thermostat tube leading down to the compressor compartment but no knob to control the temp like normal.

Is there one on these?

[collecture]

If it is like the Vendo Jr., it is a slotted head sticking out the top center of the T-stat cover/box.
Pics??