I always check the thermal cut off by removing it from the circuit. That is the easiest way to confirm -- especially if you don't have a device to test continuity. I do not recommend running your heater without it in place. Remove it to check and if it is the problem, then replace with a new one. Paul is right --- they come in packages of two and cost around $20.00 for the package. As a thought to everyone out there, I have bought the component part on Ebay before --- purchased a quantity of them for about 10 cents each and then made my own thermal cut offs --- a much cheaper way to go as the total "thing" then costs about 30 cents each.