For those that were asking about the cooler -- it's inside the silicone sleeve between the pump and the pad connector. The circuit board has a connector labeled "PTC" which I would guess is "peltier cooler". The themo sensor is also wedged into that silicone sleeve.

For those who say their unit is working but the water isn't flowing -- mine was doing that and it turned out that the metal peltier cooler was completely jammed with sediment from my tap water. When I got the thing I used distilled water like they suggested, but then I got lazy and started using tap. It took about 2 years for it to get completely blocked and stop working. I was able to clear some of it with a drill (but be careful -- there are fins inside the cooler) and then get the rest by soaking it in vinegar for a few minutes.