Oven Fan Keeps Running? How to Diagnose and Fix It

By Fix4U Team
Oven, Kitchen Appliances

It’s normal for the oven fan to run during baking to circulate hot air. But when the fan won’t shut off even after the oven is cool, frustration sets in. Why does my oven fan constantly run? How do I get it to turn off?

A continuously running oven fan is most often caused by a failure of one of the many electric components controlling the fan. With some basic troubleshooting, you can likely resolve the issue yourself.

In this guide, we’ll cover the key reasons an electric oven’s convection or cooling fan never stops, along with the steps to properly diagnose and fix the problem.

Why Does the Oven Fan Keep Going?

Electric ovens have two different internal fans:

Fixing The Oven Fan Keeps Running Problem By Fix4U Repairs In Gta

Convection Fan – Circulates hot air during convection baking modes. Should turn off shortly after the oven turns off or finishes preheating.

Cooling Fan – Kicks on after baking to hasten oven cool-down. Designed to run until the oven cavity reaches a safe temperature.

When either fan remains constantly running, suspect an issue with the electrical components controlling the fan motor:

  • Faulty main control board – Controls all oven functions including fans. Electrical issues can cause it to constantly engage the fan relay.
  • Bad fan thermostat – Cycles the convection fan based on temperature. If stuck closed, the fan never turns off.
  • Failed cooling fan thermostat Turns the cooling fan on/off based on the oven cavity temp. Defects can leave it stuck on.
  • Damaged door latch switch – Provides safety cutoff of oven components when open. A broken switch can fail to stop the fan when door opens.
  • Shorted fan motor – Rare, but electrical short in the motor windings can keep it spinning continuously.

Now let’s explore how to systematically diagnose an oven fan that refuses to turn off after baking.

Step-by-Step Troubleshooting of an Oven Fan That Runs Non-Stop

Follow these steps to pinpoint the failed component causing the fan to remain constantly on:

1: Let the Oven Cool Completely

Before doing anything, allow the oven to fully cool to room temperature after the last bake cycle. The cooling fan is designed to operate until the oven cavity temperature drops below around 150°F.

If the oven is still warm or even slightly hot, the cooling fan will stay activated until safe temps are reached. Give it several hours to completely cool off before diagnosing fan operation.

2: Check the Oven’s Main Control Board

The main PCB control board controls all the oven’s electronic components. If it starts overheating, shorts out, or suffers loose wiring connections, it can improperly engage the fan relay indefinitely.

Examine the control board for any signs of damage – discoloration, fluid leaks, burnt spots, or damaged wiring connectors. Use a multimeter to check for shorts on the board or entering/leaving the fan relay.

Also look for any error codes displayed on electronic control boards. Certain codes like F7 suggest control board faults that require replacement of the entire assembly.

Issues with oven control boards often require professional service to fully diagnose and repair. Don’t attempt disassembly or parts replacement unless you have in-depth appliance repair experience.

3: Test the Fan Thermostat

The dedicated fan thermostat switches the convection fan on/off based on air temperature inside the oven. It prevents the fan from running when not needed.

Locate the fan thermostat either near the fan shroud or mounted along the oven back wall. It has a plastic body capped with a moveable dial or coil spring.

With the oven fully cool and power disconnected, check that the thermostat dial/switch actuates when rotated from high to low temperature settings. If not, the thermostat has failed.

You can also use a multimeter to check for proper continuity. Follow your oven’s wiring diagram to identify and test the thermostat contacts that open/close at temperature thresholds. A stuck closed thermostat that lacks resistance when cool will need replacement.

4: Test the Cooling Fan Thermostat

Similar to the fan thermostat, this thermostat monitors air temperature inside the oven cavity and engages the cooling fan accordingly. When stuck in a closed circuit condition, the cooling fan never stops.

Unplug the oven and locate the cooling fan thermostat, typically near the main fan housing. Visually check for damage before testing with a multimeter. You want to see high resistance at room temperature, and continuity when heated with a hair dryer to over 100°F. Replace it if the thermostat remains closed when cool.

Newer oven models may have an electronic temperature sensor rather than a bimetal thermostat switch. Still, testing procedure is similar – check for proper resistance ranges at cool and heated temperatures according to your manufacturer’s specifications.

5: Inspect the Door Latch Switch

The latch keeps the oven door tightly closed during operation. A switch tied to the latch mechanism cuts power when the door opens as a safety precaution.

A broken door switch can remain permanently closed so that the fan keeps running even with the door open.

Inspect the door latch for damage or loose fit that could disrupt proper switch actuation. With oven unplugged, check for continuity across the door switch terminals with the door open versus closed. If you still get continuity when open, replace the faulty switch.

6: Check the Fan Motor Windings

In rare cases, the fan motor itself can malfunction and keep running regardless of electronic controls. This points to an internal short within the motor windings.

Unplug the oven and disconnect the fan motor wiring. Use a multimeter set to a high resistance range to check between the motor lead wires. You should see infinite resistance or OL. Any reading less than 10K ohms indicates a shorted motor requiring replacement.

7: Inspect Wiring and Terminal Connections

Damaged oven wiring and loose connections can also allow the fan motor to remain powered constantly, bypassing thermostats and electronic controls.

Thoroughly inspect the terminal blocks and wire harnesses associated with the oven fan looking for burnt, brittle, or damaged insulation. Make sure all wiring connections fit snugly when reconnected.

Repair any questionable wiring to prevent resistance heating and electrical shorts that can keep oven components running indefinitely.

Fan not stopping? Call Now to Fix Your Oven!

When to Call an Oven Repair Technician

While the troubleshooting steps above can isolate many fan issues, we strongly recommended professional diagnosis and repair in these situations:

  • Control board problems beyond simple error code checks
  • Accessing internal oven wiring or components
  • Replacement of a faulty gas valve on gas ovens
  • Complex disassembly required beyond surface components

Our technicians at Fix4U Repairs have in-depth training to safely track down and fix any oven fan defect, whether it requires control board programming, replacing faulty thermostats, or wiring repairs. Contact us at (647) 363-5205 to schedule service.

Prevention Tips to Stop Oven Fan Problems

To help avoid a constantly running oven fan in the future:

  • Keep your oven clean and avoid spills – debris and grease can lead to thermostat and control board failures over time.
  • Have your oven serviced annually by a professional – preventative maintenance helps spot problems before they leave your oven fan running indefinitely.
  • Use a surge protector – Helps protect sensitive electronic oven components from power spikes or electrical storms.
  • Handle the oven door gently – Slamming or impact damage can break the critical door latch safety switch.
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