I have a colman cooler thats about 25 years old the thermoelectric cooler module is defective and I would like to replace it. I have order the part on Amazon I kinda understand how it works but Im not sure about the sensor in the picture what it does and how to test or if I should replace it.
Im thinking is a temp sensor to maybe shut off the thermoelectric module if it gets to hot

 

I agree, that looks like a thermal cutout. It might be like a thermostat - meaning it can survive thousands of cycles - or it could be a one-shot fuse. My guess is the former.

At room temperature it will likely show continuity, and will go open at a high temperature. That temperature may be written on it and if you really want, you can test it on a hotplate, griddle or such.

Just wondering, how can you be sure the module is bad if you don't know whether that thermostat is good?

 

When I took the heat sinks off one wire came off the module. There only $10 for 2 so I ordered a new one.
Thanks for the info

 

When I took the heat sinks off one wire came off the module. There only $10 for 2 so I ordered a new one.
Thanks for the info

Ah, got it. So whatever problem that caused you to open this up in the first place is still an unknown?

Also, note these devices have a polarity and so you need to install it taking care that the cold side is where it's meant to be.

 

Ok. So I'm thinking I apply voltage for 30 seconds or so see what side is hot and what side is cool. Then I stall cool side facing inward. Then if I reverse polarity with the switch on the cooler the module should get hot on the inward side and cool outward. Sound correct

 

Ok. So I'm thinking I apply voltage for 30 seconds or so see what side is hot and what side is cool. Then I stall cool side facing inward. Then if I reverse polarity with the switch on the cooler the module should get hot on the inward side and cool outward. Sound correct

Yes, once you know the polarity, you can install and wire it to achieve the desired effect. But don't go 30 seconds, think more like 3! It's easy to overheat the module if it's naked, with no heat sink and fan. I've used a car battery to run a quick test, but I prefer using the 5V output of an old computer PSU. Fast damage is far less likely on 5V than 12V, since the current is so much lower.