November 1, 2015

How to replace a downdraft vent fan control switch

By Lyle Weischwill
How to replace a downdraft vent fan control switch

This DIY repair guide explains how to replace a fan control switch on a downdraft vent. Located on the upper right side of the vent, the fan control switch activates the blower fan motor and controls the blower speed. If the fan control switch wears out or breaks, it won't start the fan motor or control the speed. Replace the fan control switch with the manufacturer-approved replacement part.

This repair guide and video shows how to replace the vent fan control switch in Kenmore and Broan downdraft vents.

Quick links
Tools required
Work gloves
Phillips screwdriver
Wire cutter
1/4-inch nut driver
Repair difficulty
Time required
30 minutes or less
Repair difficulty
Time required
30 minutes or less
How to replace a downdraft vent fan control switch repair guide video.

Replacing a downdraft vent fan control switch video.

Instructions

  1. 01.

    Disconnect power and remove the downdraft vent from the counter

    Unplug the cooktop and the downdraft vent.

    Remove the cooktop from the counter. Remove the downdraft vent from the counter. Wear work gloves to protect your hands.

    Tip: Use the installation manuals for the cooktop and downdraft vent to guide you when removing the appliances from the counter.
  2. 02.

    Remove the gear motor cover

    Remove the mounting nuts from the clamp channels and then remove both clamp channels.

    Remove the screws from the gear motor cover.

    Pull the gear motor cover up.

    Disconnect the gear motor wires and then pull the wires out of the gear motor cover.

    Remove the clamp channel nuts.

    Remove the clamp channel nuts.

    Remove the clamp channels.

    Remove the clamp channels.

    Remove the gearbox cover screws.

    Remove the gearbox cover screws.

    Remove the gear motor cover.

    Remove the gear motor cover.

    Disconnect the gear motor wires.

    Disconnect the gear motor wires.

  3. 03.

    Remove the blower housing assembly

    Carefully tilt the top of the blower housing up and disconnect the blower motor wire harness. Remove the blower housing assembly.

    Tilt the blower housing up.

    Tilt the blower housing up.

    Disconnect the blower motor wires.

    Disconnect the blower motor wires.

  4. 04.

    Remove the air box cover

    Remove the mounting screws from the air box cover and pull off the air box cover.

    Remove the air box cover screws.

    Remove the air box cover screws.

    Pull the air box cover off.

    Pull the air box cover off.

  5. 05.

    Remove the fan control switch

    Unplug the wire harness for the fan control switch.

    Cut the wire tie that secures the fan control switch wire harness to the green ground wire.

    Pull the air vent up to access the fan control switch.

    Remove the mounting screws and pull the switch cover off.

    Remove the screws from the switch bracket.

    Slide the switch bracket downward and then pull the bracket out.

    Pull the knob off the fan control switch stem.

    Remove the fan control switch mounting nut.

    Pull the fan control switch out of the switch bracket.

    Disconnect the up/down switch wires.

    Cut off the wire tie from the switch bracket to release the fan control switch wires. Remove the fan control switch.

    Unplug the fan control switch wire harness.

    Unplug the fan control switch wire harness.

    Remove the switch cover screws.

    Remove the switch cover screws.

    Remove the switch bracket screws.

    Remove the switch bracket screws.

    Slide out the switch bracket.

    Slide out the switch bracket.

    Pull off the control knob.

    Pull off the control knob.

    Remove the control switch mounting nut.

    Remove the control switch mounting nut.

    Pull the control switch out.

    Pull the control switch out.

    Cut off the switch harness wire tie.

    Cut off the switch harness wire tie.

  6. 06.

    Install the new fan control switch

    Connect the up/down switch wires.

    Secure the fan control and the up/down activating switch wires to the switch bracket using a wire tie.

    Reinstall the fan control switch on the switch bracket and secure it using the mounting nut.

    Reinstall the fan control knob on the stem of the fan control switch.

    Slide the switch bracket into the vent and reinstall the bracket screws, leaving the screws loose.

    Adjust the switch bracket so that the activation switch lightly touches the membrane pad.

    Tighten the bracket screws firmly.

    Reinstall the switch cover and secure it using the mounting screws.

    Push the air vent down into the air box.

    Plug in the fan control switch wire harness.

    Connect the fan control switch wire harness to the green ground wire using a wire tie.

    Tip: There are no threads on the plastic stem of the new switch. Thread the nut straight on and it will create its own threads.
    Tip: Mounting the switch bracket up too high will keep the switch depressed and the vent will raise and lower continuously when you restore power.
    Warning: Don't pinch any switch wires when installing the switch bracket.
    Install the new fan control switch in the bracket.

    Install the new fan control switch in the bracket.

    Install the control knob.

    Install the control knob.

    Reinstall the fan switch bracket.

    Reinstall the fan switch bracket.

    Reinstall the fan control switch cover.

    Reinstall the fan control switch cover.

    Connect the fan control switch wire harness.

    Connect the fan control switch wire harness.

    Wrap the wire tie around the wires.

    Wrap the wire tie around the wires.

  7. 07.

    Reinstall the air box cover

    Position the air box cover over the air box and thread the gear motor wires through the grommet in the air box cover.

    Secure the air box cover to the air box using the mounting screws.

    Reinstall the air box cover.

    Reinstall the air box cover.

    Reinstall the cover screws.

    Reinstall the cover screws.

  8. 08.

    Reinstall the blower housing assembly

    Position the blower housing assembly on top of the air box cover.

    Tilt the blower housing assembly up and plug in the blower motor wire harness.

    Lower the blower housing assembly into place.

    Connect the blower motor wire harness.

    Connect the blower motor wire harness.

  9. 09.

    Reinstall the gear motor cover

    Thread the wires through the gear motor cover and reconnect the wires to the gear motor.

    Position the gear motor cover over the gear motor and reinstall the mounting screws.

    Reinstall the clamp channels and secure them using the mounting nuts.

    Connect the gear motor wires.

    Connect the gear motor wires.

    Reinstall the motor cover and screws.

    Reinstall the motor cover and screws.

    Reinstall the clamp channels and nuts.

    Reinstall the clamp channels and nuts.

  10. 10.

    Reinstall the downdraft vent and cooktop

    Reinstall the downdraft vent and cooktop in the counter.

Warning: Undertaking repairs or maintenance to appliances or power equipment can be hazardous. Should you choose to undertake repairs or maintenance, you are assuming the risk of injury to your person or property. In an effort to reduce the risk, use the proper tools and safety equipment noted in the applicable guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs or maintenance, however, should only be performed by a qualified technician.

Symptoms common to all downdraft ventilation systems

Choose a symptom to see related downdraft vent repairs.

Main causes: lack of electrical power, up/down activation switch failure, bad vent gear motor
Main causes: fan control switch failure, bad blower fan motor, broken blower wheel, wiring failure
Main causes: electrical power failure, up/down activation switch problems, vent gear motor failure
Main causes: problems with the vent limit switches, up/down activation switch failure
Main causes: clogged grease filters, air duct problems, fan motor failure, broken blower wheel

Repair guides common to all downdraft ventilation systems

These step-by-step repair guides will help you safely fix what’s broken on your downdraft vent.

How to replace a downdraft vent up/down button pad

The up/down button pad located on top of the air vent engages the activating switch when pushed to raise the air vent. Replace the up/down button pad if damaged.

Repair difficulty
Time required
 15 minutes or less
November 1, 2015
By Lyle Weischwill
How to replace a downdraft vent gear motor

The gear motor raises and lowers the air vent when you push the activating switch. Replace the gear motor if defective.

Repair difficulty
Time required
 15 minutes or less
November 1, 2015
By Lyle Weischwill
How to replace a downdraft vent blower motor

The blower motor spins the fan blade that removes smoke and steam from the cooktop area. Replace the blower motor if it doesn't run when activated.

Repair difficulty
Time required
 30 minutes or less

Articles and videos common to all downdraft ventilation systems

Use the advice and tips in these articles to get the most out of your downdraft vent.

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