the way to test any heater is to measure its resistance when not plugged in.
 a broken heater will almost certainly be open circuit.
a functioning heater will have a resistance of about 10-100 ohms. depending on power and voltage
the thermostat should be short circuit when cold and open circuit when hot. try a fan heater or hair dryer to get it hot
                
 David_
                
 November 2009