Without a volt-ohm meter, Its a hit or miss deal. The FIRST thing to check is the fuses or circut breakers in the home. (I can hear you now,saying that it runs but doesn't heat) CHECK THE BREAKERS!!! If they are OK, The next place I look is the thermostat at the TOP of the heater box. If you have a meter, you should be able to read continuity thru it. if not, Thats your problem. if its OK, Then remove the HEATER and check for a broken coil.:)