If your oven stopped heating up, the problem may be that the thermal fuse has blown out. Here's how to diagnose this problem and step-by-step instructions on how to replace this vital part.
About the Thermal Fuse
The thermal fuse is a safety element that monitors your oven's temperature and shuts the appliance down if it gets too hot. Although it's unusual for thermal fuses to blow out, they often do so after the oven's self-cleaning feature is used. This is because ovens can reach temperatures of 900 degrees or more during the self-cleaning process. However, a thermal fuse may also blow out due to being defective, age or damage from external factors such as electrical shorts.
The thermal fuse only controls the oven elements, so the burners and control panel will still work even though the fuse is burned out. The bake, broil and other oven features will not, however. You can confirm the thermal fuse is the problem by performing a continuity check on the part.
How to Perform a Continuity Check on a Thermal Fuse
Performing a continuity check is very simple and can be done using a multimeter or an ohmeter.
- Set the multimeter to continuity mode (ohmeter should be set to Rx1). Touch the leads together. It should make a beeping noise indicating it is working.
- To gain access to the thermal fuse, first shut down power to the stove either by tuning off the circuit breaker or unplugging the unit.
- The thermal fuse is located in the back of the stove (consult your owner's manual for exact details), so you'll need to remove the metal panel.
- Unhook one of the wires attached to the thermal fuse and touch one lead from the multimeter to the newly exposed prong. Alternatively, you can remove both wires and touch one lead from your multimeter or ohmeter to each end of the fuse.
- If the thermal fuse is still good, you should get a reading that is above zero ohms. The thermal fuse is bad if you get a zero ohm reading or OL (open load).
Replacing the Thermal Fuse
If the thermal fuse is bad, you just need to replace it with a new one. These fuses cannot be reset. Consult your owner's manual for the correct part to purchase.
The replacement process is extremely easy, and you've already done most of the work if you've tested for continuity. The remaining steps are to remove the other lead and swap the bad fuse with the new part. Typically these fuses are bolted to the stove using a screw, so you'll need a screwdriver to detach it and install the new part. Replace the back of the stove and plug it in (or reset the circuit breaker).
Your oven should begin working like normal if the thermal fuse was the only problem. If the oven still doesn't work, then there are other issues that must have arisen in conjunction with the thermal fuse blowing.
Other possible causes of a malfunctioning oven include:
- A broken thermostat. This is particularly likely if the oven broke after a self-cleaning cycle that also damaged the thermal fuse. The oven thermostat regulates the oven's temperature. If it is broken or defective, it could have caused the oven to get too hot during the self-cleaning cycle, leading to a broken fuse.
- A damaged control board. For one reason or another, the oven is not receiving commands from the control board.
- Baking or boiling elements are burned out. These should turn red hot when the oven is on. If they don't or there's blistering and other damage around the elements, then they need to be replaced.
Replacing a thermal fuse is an easy repair. If you're still having problems, though, it's best to connect with an appliance repair company for assistance with diagnosing and fixing your non-functioning oven and to get more information as to why it's broken.