May 1, 2014

How to replace a window air conditioner ambient thermistor

By Lyle Weischwill
How to replace a window air conditioner ambient thermistor

This DIY repair guide explains how to replace the ambient thermistor in a window air conditioner. The ambient thermistor is a sensor that detects the room air temperature so the electronic control board can regulate the room temperature. If the thermistor isn't working, the air conditioner won't maintain the temperature you set. Replace a malfunctioning ambient thermistor with the manufacturer-approved replacement part.

Use this procedure to replace the ambient thermistor in Kenmore, Frigidaire, Crosley, GE, Haier and LG window air conditioners.

Quick links
Tools required
Phillips screwdriver
Work gloves
Repair difficulty
Time required
45 minutes or less
Repair difficulty
Time required
45 minutes or less

Instructions

  1. 01.

    Disconnect electrical power

    Unplug the power cord from the wall outlet.

  2. 02.

    Pull the air conditioner out of the window

    Remove the screws that hold the accordion filler panels in the window frame.

    Push the accordion filler panels inward to clear the window frame.

    With someone’s help, support the air conditioner and raise the window sash.

    Carefully lift the air conditioner out of the window and set it on a stable work surface.

    Place the air conditioner on a stable work surface.

    Place the air conditioner on a stable work surface.

  3. 03.

    Remove the front grille panel and filter

    Grasp the sides of the front grille panel at the top and pull the front grille panel out and off of the air conditioner.

    Pull the filter out.

    Tip: Take this opportunity to clean the air filter if necessary.
    Remove the air filter.

    Remove the air filter.

  4. 04.

    Remove the control panel

    Remove the screws from the sides and bottom of the control panel.

    Pull the control panel up and hold it above the air conditioner. Unplug the wire harness connection for the user interface control board.

    Set the control panel aside.

    Remove the screws from the sides of the control panel.

    Remove the screws from the sides of the control panel.

    Remove the screws from under the control panel.

    Remove the screws from under the control panel.

    Pull the control panel up and hold above the air conditioner.

    Pull the control panel up and hold above the air conditioner.

  5. 05.

    Remove the front panel

    Remove the screws from the sides of the front panel.

    Pull the front panel off of the air conditioner and set it aside.

    Remove the screws from the sides of the front panel.

    Remove the screws from the sides of the front panel.

    Pull the front panel off the air conditioner.

    Pull the front panel off the air conditioner.

  6. 06.

    Remove the outer case

    Remove the screws from the exterior of the outer case.

    Remove the center stop for the accordion filler panels. Remove the hidden screw that is under that center stop.

    Pull outward on the bottom of the outer case and remove the outer case from the air conditioner.

    Remove the screws from both sides of the outer case.

    Remove the screws from both sides of the outer case.

    Remove the screws on top of the outer case.

    Remove the screws on top of the outer case.

    Remove the screws on the back of the outer case.

    Remove the screws on the back of the outer case.

    Remove the outer case.

    Remove the outer case.

  7. 07.

    Remove the ambient thermistor

    Remove the screws from the electronic control board case. Pull out the cover of the electronic control board case to expose the electronic control board.

    Disconnect the black ambient thermistor wire from the T1 connector on the electronic control board.

    Pull the ambient thermistor out of the mounting clip on the front of the evaporator.

    Remove the screws from the control board case.

    Remove the screws from the control board case.

    Disconnect the black ambient thermistor wire from T1 connector on the control board.

    Disconnect the black ambient thermistor wire from T1 connector on the control board.

    Pull the ambient thermistor out from the mounting clip.

    Pull the ambient thermistor out from the mounting clip.

  8. 08.

    Install the new ambient thermistor

    Insert the new ambient thermistor in the mounting clip on the front of the evaporator.

    Plug the wire harness for the ambient thermistor into the T1 connector on the electronic control board.

    Position the cover of the electronic control board case in place and reinstall the screws.

    Tip: Make sure that wires aren’t pinched when reinstalling the electronic control board cover.
  9. 09.

    Reinstall the outer case and front panel

    Position the outer case properly on the air conditioner.

    Reinstall the screws in the outer case including the hidden screw in the center.

    Position the front panel on the air conditioner and reinstall the mounting screws on the sides of the front panel.

  10. 10.

    Reinstall the control panel

    Position the control panel above the air conditioner and plug the user interface control wire harness back in.

    Position the control panel on the front of the air conditioner and reinstall the mounting screws in the control panel.

  11. 11.

    Reinstall the front grille panel and filter

    Insert the filter on the front of the air conditioner.

    Position the front grille panel on the front of the air conditioner and snap the grille panel into place.

  12. 12.

    Restore the power

    Plug the air conditioner into the electrical outlet.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the 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 should only be performed by a qualified technician.

Symptoms for window air conditioners

Choose a symptom to see related window air conditioner repairs.

Main causes: bad compressor, lack of refrigerant, bad compressor start relay, electronic control board failure
Main causes: turning the air conditioner off and the back on too quickly, dirty or restricted condenser coil, compressor failure
Main causes: dirty air filter, air conditioner is too small for the room, temperature set too cold, control failure
Main causes: clogged drain hole, air conditioner not leveled properly
Main causes: clogged condensate drain, air conditioner not leveled properly, leaky window air seals
Main causes: lack of electrical power, bad electronic control board, wiring failure, bad temperature sensor

Repair guides for window air conditioners

These step-by-step repair guides will help you safely fix what’s broken on your window air conditioner.

How to replace a window air conditioner ambient thermistor

If your window air conditioner isn’t cooling properly, it might need a new ambient thermistor. You can replace it yourself following these instructions.

Repair difficulty
Time required
 45 minutes or less
How to replace a window air conditioner user interface control board

Control buttons or lights on the user interface control board can stop working. This repair guide shows how to replace it.

Repair difficulty
Time required
 30 minutes or less
How to replace a window air conditioner electronic control board

The electronic control board is the brain of your window air conditioner. Here’s how to replace it.

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all room air conditioners

Use the advice and tips in these articles and videos to get the most out of your window air conditioner.

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